Hi Juri,

I recently came across a regression of performance in Emacs for describe bindings, which I have reported as bug#45379. After bisection, the offending seems to be a commit a649034336 you pushed in November 2020, to fix bug#5423. Since I have received no reply after bug#45379 was reported (more than 2 weeks), I guess it's better to contact you and cc every participants of bug#5423. I am including the description of the bug report here for your convenience.

> `describe-buffer-bindings` has become significantly slower since the
following commit

a649034336 * bad Don't show key ranges if shadowed by different commands

This also makes `describe-bindings` and anything depending on it hardly
usable. For me, it takes about 2 seconds on vanilla Emacs in an org-mode
buffer, and a few minutes on my Emacs configuration (was almost instant
before the offending commit).
> 

Sheng Yang(杨圣), PhD candidate
Computer Science Department
University of Maryland, College Park
E-mail: styang@fastmail.com
E-mail (old but still used): yangsheng6810@gmail.com