Just noticed in Webmin -> Servers -> MySQL Database Server -> Global Options, User Permissions, a Unix user account which is longer than 16 characters is truncated. It’s also truncated when you click through to modify the account’s permissions.
I’ve not checked against a database to see whether the permissions actually apply OK to the account when changes are made, however it looks like it may only be a visual bug, as altering permissions on the account via the form does appear to work.
This caught me out - not used MariaDB before. Googling around the other day before asking, I got the impression <=80 chars was supported as of MariaDB 5.5.31 (this server is using 5.5.64); https://github.com/sequelpro/sequelpro/issues/1886
I haven’t paid close attention to that limit. I think it’s probably fine to leave it at 16 for a while, until all the 16 limited versions have gone out of use, and then we can bump it to 32 (the least common denominator).