I often run into situations where I'm reading a book and get stuck at certain sentence. These are places where authors assume the implication follows obviously, but due to certain reasons (lack of familiarity with the subject, with previous chapters etc.), I fail to see it. All I need is 2-3 sentences more to explain this particular step. These type of a questions usually can be answered within a few lines. In other words, these are small bottlenecks I run into during learning.
Usually I bring these questions to my professors, but since they occur very often, and they usually require getting into the technicality of reading the whole proof, getting used to the notation etc, I don't always get a reply.
That's why I created the tag. I have seen many questions like these before, but at time of creation I could only tag a few, starting with my own.
I don't think it is similar to proof-verification. In proof-verificatio the asker knows the idea of the proof but lack execution or need verification. But here the asker need explanation of an indea which he failed to see through.
Regarding what Grigory M and Martin Sleziak said, at least my purpose for this tag is not to seek intuition behind proofs, nor am I seeking explanation of the whole proof, but rather a specific line about a specific implication which needs only very short answer.