(Ooops, I wasn't aware that this is upstream and not Wikimedia's Phabricator. Anyway, the comment is still relevant.)

I think you want to filter by project ID, adding projects explicitly to a whitelist, and not on project type. Icons and colors alone won't tell you whether a task is on or off-topic for wikibugs.

Just to clarify, it's not for filtering tasks, but for filtering which projects are included in the IRC message. Thatt is, we'd like the format to be

<list of projects>: <title> - <link> (<user>) <description of change>

not

<list of all tags>: <title> - <link> (<user>) <description of change>

(e.g.

22:42 <wikibugs2> Community-Engagement, ECT-November-2014, Engineering-Community, ECT-October-2014, Bugzilla-Migration, RT-Migration: Communicate the launch of Wikimedia Phabricator Day 1 - https://phabricator.wikimedia.org/T188#20055 (Whatamidoing-WMF) Scheduling IRC office hours is very easy: you just add yours to the list...

should be

22:42 <wikibugs2> Bugzilla-Migration, RT-Migration: Communicate the launch of Wikimedia Phabricator Day 1 - https://phabricator.wikimedia.org/T188#20055 (Whatamidoing-WMF) Scheduling IRC office hours is very easy: you just add yours to the list...

at least in the regular IRC channels.

Thanks for the quick clarification. I understand now.

• T5873 discusses general treatment of edge relationships, like watchers.
• Flags can already be queried with flag.query. They're also personal to the viewer. We're unlikely to expose them by default in other application query methods.
• Description is a CustomField and covered by T5873.
• Color and icon are primary fields, straightforward to expose, and uncontentious (except possibly that the internal icon name is prefixed with "fa-" for "FontAwesome", which feels like somewhat of an implementation detail). I'd be happy to accept a diff to add them to both the parameters and output in advance of T5873.
• Policies are also primary fields and straightforward, but there's generally no way to query for policy information after you have them. You can recognize common policies (public/users) but can't decode a custom policy over the API right now. So probably this is an easy first have and then an involved second half.

After D15105:

• Colors, icons and policies and custom fields are available via project.search.
• Members and watchers are available via project.search by querying for appropriate attachments.

Flags have always been available via flag.query. Flags are personal to the viewer, so I do not plan to expose flag information in other applications' API methods.