A tag with more than one possible but conflicting definition is a tag that should be cleansed with the fires of burnination. An ambiguous tag is a bad tag. No amount of tag wiki contributions will ever be able to successfully resolve the conflict among the multiple definitions.
When alerted to the possible conflict because you were reviewing edits, you should consider doing what you've just done -- popping over to Meta to get some opinions on the matter. Shortly thereafter, one of us righteous tries-to-do-gooders will come along and spout some hot air about the matter.
There are a lot of naming conflicts in the software world. If at all possible, multiple tags should be created to resolve naming conflict ambiguity in a completely unambiguous way. When possible, disambiguation of a tag name should make it obvious which is what and who is where. For example, quartz was deemed excessively ambiguous. It was split into quartz-scheduler and quartz-graphics in order to remove the ambiguity.
In the case of psr, the course is clear. The Windows Problem Steps Recorder should not be acronymized, and any PHP questions talking about "PSR" without a number need retagging.
I've created problem-steps-recorder for the PSR questions. Please examine the questions closely, as one of the three requires some closevote TLC. I have not created an excerpt or wiki.
Of the remaining questions, most (1, 2, 3, 4, 5) were related to but not directly about the PSR-1 and PSR-2 coding standards. Most had and all now have the coding-style tag, which sufficiently classified them. Two were hard questions about PSR-2 itself, thus actually suggesting psr-2 as a thing. I've added a simple excerpt and stub wiki for people that can't Google.
One was actually about psr-3 and has been appropriately reclassified. I've added a simple excerpt and pathetic stub wiki for people that can't Google.
As of now, psr is empty. I've added it to my list of 123 tags I try to prevent from coming back from the dead.