[w3c/manifest] Make BeforeInstallPrompt optional (#797)

Closes #???

This change (choose one):

* [ ] Breaks existing normative behavior (please add label "breaking")
* [ ] Adds new normative requirements
* [ ] Adds new normative recommendations or optional items
* [ ] Makes only editorial changes (only changes informative sections, or
  changes normative sections without changing behavior)
* [ ] Is a "chore" (metadata, formatting, fixing warnings, etc).

Implementation commitment (delete if not making normative changes):

* [ ] Safari (link to issue)
* [ ] Chrome (link to issue)
* [ ] Firefox (link to issue)
* [ ] Edge (public signal)

Commit message:

(Fill in. If making normative changes, describe exactly what the behavioral
difference will be.)

You can view, comment on, or merge this pull request online at:

  https://github.com/w3c/manifest/pull/797

-- Commit Summary --

  * Make BeforeInstallPrompt optional

-- File Changes --

    M index.html (6)

-- Patch Links --

https://github.com/w3c/manifest/pull/797.patch
https://github.com/w3c/manifest/pull/797.diff

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/w3c/manifest/pull/797