tickets from Sage Days: please review

[Lorenz Panny]

Sage Days 123 in Leuven ended yesterday and quite a few pull requests
have come out of it already, most of them from new contributors. 🎉
I would like to encourage potential reviewers to have a look at them
sooner rather than later in order to hopefully keep some of the fresh
momentum alive. (Please bear in mind that many of the patch authors
are new to Sage development and may therefore benefit from slightly
more detailed feedback than some of the more seasoned developers.)
Thanks in advance!