Could someone clarify the preferred syntax for magic strings in changelists?

R=
TBR=
BUG=
NOTRY=
etc.

Prior to Gerrit, the syntax was, e.g. BUG= 12345 . In Gerrit the preferred syntax seems to be Bug:  12345 .

Are they both valid?

I noticed that TBR: foo does NOT seem to work while TBR=foo does. That seems inconsistent - we should either switch to just one valid syntax, or allow both forms for everything.

Specifically, if you set TBR: foo, Gerrit doesn't prompt you to CR+1, whereas if you set TBR=foo, it does. Haven't checked whether the CQ accepts both syntaxes either. Consider this a request to please audit every part of the code that checks for these, and maybe update canonical documentation of all of them.