• When users type K1 or {K1} in remarkup, and a Passphrase credential with the associated monogram exists, it should be specially highlighted and linked.
• Implement a RemarkupRule for Passphrase, similar to the rules you implemented for dashboards in T4983.
• This doesn't need to do anything special in the {K...} embedded form, the default behavior (that is, K123: Full Name Here) is good enough.

Looks like https://secure.phabricator.com/book/phabricator/article/remarkup/ has not been updated for this new syntax?

We don't list every object type in the documentation, under the assumption that it's reasonably obvious by observing URLs and the behavior of other objects -- but maybe that assumption isn't very good. Do you think it's unclear?

https://secure.phabricator.com/book/phabricator/article/remarkup/#linking-to-objects

See also https://secure.phabricator.com/w/object_name_prefixes/

The passphrase and projects (were) are a good example of why it's unclear: Tnnn works, Dnnn works, Fnnn works, Mnnn works, so then you think you have figured it out and try Pnnn for projects, but it doesn't work (because of conflict with Paste) or Knnn because it's not implemented for some reason. I don't know the general rule of "take the first letter of an app and you can link to its objects" stands now though with the latest improvements.

Seems like the documentation is actually really explicit: there's a dedicated section on Mocks, Images, Projects, Tasks, Differentials... Because of this approach, at least to me, if something is not listed (like Passphrase), I assume it's because it's not supported.

Or this part of the doc would need to be rewritten using a different approach: "Except for X, Y, Z, all objects in Phabricator can be linked from Remarkup using the the first letter of their app followed by their number e.g. T123 to task 123. Add {} around the link to display more... etc..." Followed by a list of additional behaviors for some apps like Pholio.