In the meantime you can help yourself by the following methods.
Note: $char(0) represents the null value, which usually marks the end of a textstring.
If you want to put a comment into an action group, e. g. ...
1=$char(0)'Author of this Mp3tag mta action script is ...'
This way the comment is part of the mta text file, but does not create any tag-field.
... or ...
1='This is the title string'$char(0)'This is the comment string'
If you want to put a comment anywhere into a formatstring ...
Actiontype 5: Format value
Field ______: TMP_FILENAME
Formatstring: [REM Store current filename.]%_filename%
In Mp3tag the square bracket clamp has special meaning.
If the clamp contains a tag-field which does exist, then the content within the clamp will be displayed.
If the clamp does not contain any tag-field value, then the content within the clamp will not be displayed.
There is an example script ...
CD´s einer Compilation zusammenfügen