Every enabled add-on used to be activated synchronously in initAddons(),
during app.whenReady and before the window exists. That is the largest
launch cost left (boot tracer, 2026-10-03). An add-on can now say
"activation": "on-demand" in addon.json. It is then listed at launch but
not started. Its declared surfaces stay live: "panels" (new: sidebar
panels declared up front), toolbar-menu, context-menu-items and the
page-inject bridge, whose source is read on the first matching page.
activate() runs on first real use: a panel opened, a menu or context
item picked, a message from its panel, tab or page bridge, a Settings
addon-invoke, a wiz:// link (for Aegis). All of those go through
AddonHost.dispatch(), which starts the add-on and waits for it, so no
call is dropped. Concurrent callers share one activation, and
activations run one at a time.
Startup stays the default: the host cannot tell what an older add-on
does in activate(). request-filter add-ons and add-ons that declare no
surface are forced to startup. If activate() returns a promise, calls
wait for it (at most 5 s). api.startAtLaunch(bool) lets an on-demand
add-on ask to be started at launch again (for live relay sessions).
Converted: notepad, screenshot, translate, docx-editor, pdf-editor, vpn
(none has launch-time work: no file association, no auto-connect, and
add-on file tabs are not part of the saved session). Shield and Cookie
Pop-ups stay startup: Shield owns the request filter and must see the
first request; Cookie Pop-ups costs ~6 ms and acts unasked on every
page. Aegis stays startup and untouched: another session owns it. See
NOTE-aegis-on-demand.md (next commit).
Settings › Performance › Startup:
- "Start extensions when first used" (default on). Off = all at launch;
switching it off starts the waiting add-ons immediately.
- "Start the wallet at launch". Shown disabled with a hint until the
installed Aegis manifest allows on-demand. It applies with no Settings
change once Aegis opts in.
- "Preload common menus" gates prewarmOverlays().
- "Use lightest" preset.
New keys are plain SETTINGS_DEFAULTS through the existing settings-set.
No new IPC channels.
Measured: boot-trace, fresh profile, --seconds 20 so the 30 s add-on OTA
poll can't swap Aegis mid-series; warm runs 2-3 of two paired series.
- Add-on activation at launch: 121-154 ms -> 104-174 ms. The six
converted add-ons went from 16-20 ms to 0. The rest is Shield (83-148
ms, noisy) and Aegis (15 ms in this tree's 0.9.0).
- Toolbar painted: 1278-1584 ms -> 1282-1481 ms (within noise).
- With "Preload common menus" off: 0 overlays prewarmed, 8 processes
instead of 11, about 50-70 MB less at 15 s.
The bundled add-on versions are not bumped. Existing profiles keep their
old addon.json, and so stay on startup activation, until those add-ons
ship with a higher version (seedBundledAddons only reseeds a strictly
newer bundle).
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