The "test-tempname" command:

Usage: fossil test-name [--time SUFFIX] [--tag NAME] BASENAME ...

Generate temporary filenames derived from BASENAME. Use the --time option to generate temp names based on the time of day. If --tag NAME is specified, try to use NAME as the differentiator in the temp file.

If --time is used, file_time_tempname() generates the filename. If BASENAME is present, file_tempname() generates the filename. Without --time or BASENAME, fossil_temp_filename() generates the filename.