The order in which databases are attached to Datasette matters - it affects the homepage, and it's beginning to influence how certain plugins work (see simonw/datasette-tiles#8).
Two years ago in cccea85 I made /-/databases return things in alphabetical order, to fix a test failure in Python 3.5.
Python 3.5 is no longer supported, so this is no longer necessary - and this behaviour should now be treated as a bug.