I just discovered that KeePassX is no longer maintained, so I’ve moved on to KeePassXC, which is a drop-in replacement.
It looks much nicer (including a dark theme) and has a browser extension, which I’ll try soon. There are many improvements. A nice feature is the ability to generate passwords quickly without having a password database open.
It can do passphrases with several words!
And it can put extended ASCII in generated passwords. (Not Unicode, but I’ll have to try pasting some in to see what it breaks.)
KeePassDroid has the same origins and uses the same file format, so one can manage a password file with KeePassXC and then copy it to one’s Android phone and open it there with KeePassDroid.