Rene KievitsandClaude Opus 5
ef8b6b96c4
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Blocking snu.lge.com in /etc/hosts never stopped the boot popup on a CX, and the reason only showed up on the TV itself: /usr/sbin/update is a systemd unit (webos-mbd.target) that runs its version check against https://snu.lge.com/CheckSWAutoUpdate.laf 15-20 seconds before the Homebrew Channel gets as far as running its init.d hooks. The check therefore succeeds on every boot and the alert is already on screen before any hosts entry exists. Homebrew Channel's own "block system updates" toggle loses the same race. Nothing running that late can win it: every systemd unit path is a read-only overlay except tmpfs /run, and no persistent setting gates the check - automaticUpdate, support/softwareUpdateEnable, hotelMode/swUpdateEnable and .UpdateIsInprogress were each measured by restarting the daemon and counting its requests. So dismiss the popup instead. The boot hook recovers the alert id from the updater's own log (_gAlertWindowId), which is the only way to reach an alert that opened before we could subscribe - com.webos.notification never reports it to a late subscriber and closeAllAlerts rejects every source id it accepts. A companion alert-watch.sh then stays subscribed for the rest of the session. Also drop two things that were never true. There is no staged firmware image driving the popup (the staging dir is empty at boot; the size the daemon reports is in-memory only), and there is no update service to stop - /etc/init is dead upstart leftovers on a systemd TV, so the old stopServices layer printed "stopped update" while doing nothing. - rename the hook to 00-lgupdateblocker so run-parts runs it first, removing the legacy file on apply - add support/ and hotelMode/ to the scanned settings categories - stop matching "ota" inside screenRotation, which would have switched screen rotation off - kill the watcher by process group, and make its TERM trap exit - a trap that only returns resumes the script, which then re-subscribes Verified on an LG OLED55CX8LB (webOS 5, 04.60.65): after a reboot the boot log records "dismissed update popup com.webos.service.update-1788650782451", matching the id the updater logged that boot. Raised 01:26:22, closed 01:26:37 - so it is visible for ~15s and then goes away on its own. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
195 lines
9.5 KiB
Markdown
195 lines
9.5 KiB
Markdown
<p align="center">
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<img src="assets/icon400.png" width="120" alt="LG Update Blocker">
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</p>
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# LG Update Blocker
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A webOS homebrew app that gets rid of the *"a new software version is
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available"* popup LG shows on every boot — without touching the firmware
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itself, and fully reversible.
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Built for a rooted **LG CX (webOS 5)**, but nothing in it is model specific: it
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only ever probes for things and acts on what it actually finds on your TV.
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## Why blocking the update servers is not enough
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Blocking `snu.lge.com` in `/etc/hosts` is the obvious fix, and it is what the
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Homebrew Channel's own *Block system updates* toggle does. On a CX it does not
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stop the boot popup, and it took a session on the TV to work out why.
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`/usr/sbin/update` is started by **systemd** (`update.service`, pulled in by
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`webos-mbd.target`) and runs its version check against
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`https://snu.lge.com/CheckSWAutoUpdate.laf` roughly **20 seconds before** the
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Homebrew Channel gets as far as running its `init.d` hooks. So on every boot
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the check reaches a real LG server, gets `RESULT_CD 900 / Success` back, and
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the popup is already on screen by the time any hosts entry exists:
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```text
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00:20:52 [tNsuMainTask] pRequestUpdateUrl - https://snu.lge.com/CheckSWAutoUpdate.laf
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00:20:52 [updateTimer] NSU_CreateUpdateAlert - "…Version: 04.64.00…"
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00:21:11 lg-update-blocker: hosts entries added ← 19 seconds too late
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```
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Losing that race is not fixable from userspace. Every directory systemd reads
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units from is a read-only overlay except `/run/systemd/system`, which is tmpfs
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and created after the updater has already gone. Nor is there a setting that
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gates the check — `automaticUpdate`, `support/softwareUpdateEnable`,
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`hotelMode/swUpdateEnable` and the `.UpdateIsInprogress` flag were each tested
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by restarting the daemon and counting the requests it made, and none of them
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stop it.
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So this app **closes the popup** instead of trying to prevent it, and blocks
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the hostnames to stop the download and every later check in the session. Two
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things also turned out not to be true, and the app no longer pretends
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otherwise: the popup is not caused by a staged firmware image (the staging
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directory is empty at boot; the size the daemon reports is in-memory only), and
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it is not caused by an update *service* that can be stopped — `/etc/init` is
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dead upstart leftovers on a systemd TV, and `initctl stop update` silently
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"succeeds" while doing nothing.
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## Protection layers
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| Layer | What it does | Default |
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| --- | --- | --- |
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| **Block LG update servers** | Points `snu`/`su`/`nsu.lge.com`, their TLS variants, the `-dev` fallbacks and the CDN aliases at `127.0.0.1` in `/etc/hosts` | on |
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| **Close the update popup** | Closes the alert the updater raised during boot, then stays subscribed to `com.webos.notification` and closes any later one as it opens | on |
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| **Delete staged firmware** | Wipes the update image staged in `/mnt/lg/cmn_data/swupdate` if the TV ever does download one | on |
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| **Lock the staging folder** | Bind-mounts an empty read-only directory over it, so nothing can be staged again | off |
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| **Turn off auto-update settings** | Reads every `com.webos.settingsservice` category, switches off each update-related key it finds, and remembers the original values. On a CX this includes `hotelMode/swUpdateEnable`, which also hides the *Software Update* menu until you revert | on |
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Every layer is undone by **Remove protection**, which also restores the
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settings from the backup it made.
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Be honest about what this buys you: the popup is closed within a fraction of a
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second of the Homebrew Channel starting its hooks, but the updater raised it
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15–20 seconds earlier, so on a cold boot **you will see it appear and then
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vanish by itself**. It is gone before you can act on it, and you never have to
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dismiss it. The hook is installed as `00-lgupdateblocker` so `run-parts` runs
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it before the other homebrew hooks, which is as early as anything unprivileged
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can go. Measured on a CX: alert raised at `01:26:22`, closed at `01:26:37`.
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## Requirements
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* A rooted webOS TV with the [Homebrew Channel](https://github.com/webosbrew/webos-homebrew-channel)
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installed and its root status showing **ok**.
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* The app's own service needs root. On first launch it asks the Homebrew
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Channel to elevate it (`elevateService`, falling back to running
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`elevate-service` through `exec`), then restarts itself. The header badge
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turns green when it worked.
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## Install
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### Through the Homebrew Channel (repository)
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Add the repository once — *Homebrew Channel → Settings → Add repository*:
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```text
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https://git.crylia.de/Crylia/lg_update_blocker/releases/download/latest/apps.json
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```
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The app then shows up in the Homebrew Channel list, and every new release that
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is tagged is picked up automatically — Gitea resolves `.../download/latest/...`
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to the newest release.
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### Manually
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Download the `.ipk` from the release and:
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```sh
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ares-install com.rkievits.lgupdateblocker_<version>_all.ipk
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ares-launch com.rkievits.lgupdateblocker
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```
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## Using it
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Navigate with ▲▼, select with OK, leave with BACK.
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1. Check the layers you want (the defaults are a good start).
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2. **Apply protection** — the log pane shows exactly what was changed.
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3. Reboot and confirm the popup is gone.
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Other buttons: **Purge staged update** (wipe a downloaded image right now),
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**Remove protection** (undo everything), **Refresh status**, and
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**Diagnostics** (dumps OS info, mounts, discovered settings, the tail of
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`/etc/hosts` and the boot-hook log — handy for a bug report).
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## What it touches
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| Path | Purpose |
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| --- | --- |
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| `/etc/hosts` | Blocked hostnames, between `# >>> lg-update-blocker >>>` markers. Bind-mounted from `/tmp/lgupdateblocker-hosts` because `/` is read-only |
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| `/var/lib/webosbrew/init.d/00-lgupdateblocker` | Boot hook, run by the Homebrew Channel startup script; re-applies the enabled layers. The `00-` prefix makes `run-parts` run it first |
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| `/var/lib/webosbrew/lgupdateblocker/` | `config.json`, `hosts.txt`, `settings-backup.json`, `boot.log`, `alert-watch.sh` |
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| `/tmp/var/log/update.log` | Read only — the updater logs the id of the alert it raised, which is the only way to close a popup that opened before we were subscribed |
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| `/mnt/lg/cmn_data/swupdate` | Staged firmware, emptied (and optionally locked) |
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Nothing is written to system partitions, and no LG binaries are patched or
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replaced.
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## Troubleshooting
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* **Badge says "no root"** — open the Homebrew Channel, verify *Root status* is
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`ok`, then relaunch this app. If the Homebrew Channel itself is unelevated,
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fix that first (its Settings screen has a button for it).
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* **Popup still appears after a reboot** — run *Diagnostics* and look at the
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boot-hook log at the bottom. It records, per boot, whether the hosts entries
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were added, what was purged, and the id of the popup it closed. If there is
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no `dismissed update popup …` line, check `updateLog` in the same dump for
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`_gAlertWindowId` — if that is missing too, your TV raises the alert by some
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other route and the diagnostics dump is what to open an issue with.
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* **The popup appears for ~15 seconds, then disappears on its own** — expected, see
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[Why blocking the update servers is not enough](#why-blocking-the-update-servers-is-not-enough).
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Nothing running after the Homebrew Channel can beat the updater to it.
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* **Belt and braces** — a hosts file only helps if the TV uses DNS. Blocking
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`snu.lge.com`, `su.lge.com` and `nsu.lge.com` on your router or Pi-hole as
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well is the one measure that also survives a factory reset.
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* **Forced *app* updates** (the *"You must update this app to launch it"*
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dialog) are a different mechanism — that is what
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[LG App Update Blocker](https://github.com/dr0dr1dr2dr3/lgappupdateblocker)
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is for. This app deliberately leaves the `lgtvsdp.com` hosts alone, since
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blocking those also breaks the store and several other services.
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## Building
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No bundler, no runtime dependencies — `tools/build.js` copies `app/` and
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`service/` into `build/` and substitutes the app id and version.
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```sh
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npm install # only the ares CLI
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npm run dist # build + package + manifest, output in dist/
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npm run deploy # ares-install the resulting ipk
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```
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## Releasing
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[.github/workflows/release.yml](.github/workflows/release.yml) builds on every
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push (Gitea Actions reads `.github/workflows/` too). Tag a commit `v<version>`
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(matching `version` in `package.json`) and the workflow additionally publishes a
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release containing:
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* `com.rkievits.lgupdateblocker_<version>_all.ipk`
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* `com.rkievits.lgupdateblocker.manifest.json` — Homebrew Channel manifest,
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with the absolute ipk URL, its sha256 and size
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* `apps.json` — the one-package repository index used by the repository URL above
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* `description.html` — the long description shown in the Homebrew Channel
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Uploading is done by [tools/release-gitea.js](tools/release-gitea.js) against
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the Gitea API (`softprops/action-gh-release` only speaks to github.com). It is
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idempotent: re-running a tag reuses the release and replaces the attachments.
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The URLs inside the manifest come from `PUBLIC_SERVER_URL` in the workflow, not
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from `GITHUB_SERVER_URL` — the runner is handed the instance's internal LAN
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address, which the TV cannot reach. Change that one variable if the instance
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moves. Generating for github.com instead works too: `--server` (or
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`PUBLIC_SERVER_URL`) switches the "latest release asset" URL to GitHub's shape.
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The app id lives in exactly one place: the `name` field of `package.json`.
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Change it there and everything (appinfo, service name, Luna URIs, manifest)
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follows.
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## License
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MIT
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