Proposal: Add permanentNodeType property to BookmarkTreeNode

[oliverdunk]

Proposal

Add a new permanentNodeType property to BookmarkTreeNode, with a new PermanentNodeType enum:

• BOOKMARK_BAR
• OTHER
• MANAGED
• MOBILE

This could be optional, or set to a NOT_PERMANENT / NONE value for other nodes.

Individual browser vendors could add additional variants to this enum.

Motivation

It is typical for browsers to have a number of permanent nodes at the top-level of the bookmarks tree.

For example, Chrome, Edge and Firefox all have a variation of the bookmarks bar concept.

Identifying these children is currently not possible in a robust way:

By ID

The IDs are not consistent between browsers:

• These have numerical (albeit string) IDs in Chromium browsers
• These have special IDs like "toolbar_____" in Firefox

Additionally, in Chromium based browsers the ID is normally predictable but can change in rare cases.

By name

The names are also not consistent and may change over time.

[Rob--W]

Suggested name folderType instead of permanentNodeType, per discussion from the meeting:

webextensions/_minutes/2024-12-19-wecg.md

Lines 171 to 183 in edd0979

	[Issue 732](https://github.com/w3c/webextensions/issues/732): Proposal: Add `permanentNodeType` property to BookmarkTreeNode
	* [oliver] The name we had in mind there was `systemNodeType`.
	* [rob] Any opinions on the Safari side?
	* [timothy] Don't know if system needs to be in the name if there's already a nodeType(?)
	* [oliver] There's already a BookmarkTreeNode.type.
	* [timothy] Maybe `nodePurpose`? Or maybe just `purpose` makes sense?
	* [tomislav] Something like ownership may make more sense?
	* [rob] What stops us from reusing nodeType and expanding the supported values?
	* [oliver] It is still a folder. If you're building UI that wants to show different types of folders, you may want to change the icon based on the type, for example.
	* [rob] Call it `folderType`, since only folders can have this?
	* [oliver] Can't think of a reason not to.
	* [timothy] I like that, feels nice.