MariaDB starting with 10.4.6
MariaDB starting with 10.5.2
From MariaDB 10.5.2,
mysql_fix_extensions is the symlink, and
mariadb-fix-extensions the binary name.
mariadb-fix-extensions converts the extensions for MyISAM (or ISAM) table files to their canonical forms.
It looks for files with extensions matching any lettercase variant of
.ism and renames them to have extensions of
.ISM, respectively. This can be useful after transferring the files from a system with case-insensitive file names (such as Windows) to a system with case-sensitive file names.
Invoke mariadb-fix-extensions as follows, where data_dir is the path name to the MariaDB data directory.