When trying to run linkchecker with only linkchecker itself keyworded (i.e. with stable dev-python/requests), $ linkchecker This program requires Python requests 2.2.0 or later. buuuuuttttt it doesn't work with =dev-python-requests-2.2.0 either. I had to go up to 2.2.1 (also in portage) before linkchecker would run. So it looks like that's the lower bound it needs.
Created attachment 387176 [details] linkchecker-9.2-r1.ebuild This isn't as big of a deal now that =dev-python/requests-2.3.0 is stable, but you can still hit it if something else pulls in =dev-python/requests-1.2.3.
=dev-python/requests-1.2.3 is gone, so is the problem =)