My system configuration had a problem with a particular package sometime between now and the 16th, but using git I was able to track down precisely which source was causing the problem and then with a little googling I was able to find which app was broken and update the rest of the way. This is a power that #Nixos has given me that I never had all those years running Ubuntu.
I know it's possible to instruct that particular app to pull from the older source, but I'm not there yet.
#linux