Regions are initially named using either:
These are not audio files, but regions that represent the full extent of an audio file. Every time a new recording is done, or a new file is embedded/imported, a new region is created that represents the entire audio file(s) This region will have the name of the track/playlist/original file, followed by a "-" and then a number plus a dot and then a number.
For recorded regions, the number will increase each time a new recording is made. So, for example, if there is a playlist called "Didgeridoo", the first recorded whole file region for that playlist will be called "Digderidoo-1". The next one will be "Digeridoo-2" and so on.
For imported/embedded files, the region name will be based on the file name, but with any final suffix (e.g. ".wav" or ".aiff") removed.
Normally, whole file regions are not inserted into tracks/playlists, but regions derived from them are. The whole-file versions live in the editor region list where they act as an organizing mechanism for regions that are derived from them.
When a region is inserted into a track/playlist, its initial name will end in a version number, such as ".1" or ".103". For a recorded region, if the whole file region was "Hang drum-1", then the region in the track will appear with the name "Hang drum-1.1". For an imported/embedded region, if the whole file region was "Bach:Invention3", then the region in the track will appear with the name "Bach:Invention3.1".
If you copy a region, it initially shares the same name as the original. When you perform an operation modifies one of the copies, Ardour will increment the version number on the particular copy that changed.
You can rename a region at any time. Use the region context menu to popup the Rename dialog. The new name does not need to have a version number in it (in fact, it probably should not). Ardour will add a version number in the future if needed (e.g. if you copy or split the region).