The "test-looks-like-utf" command:

Usage: fossil test-looks-like-utf FILENAME

Options:

-n|--limit N

Repeat looks-like function N times, for performance measurement. Default = 1

--utf8

Ignoring BOM and file size, force UTF-8 checking

--utf16

Ignoring BOM and file size, force UTF-16 checking

FILENAME is the name of a file to check for textual content in the UTF-8 and/or UTF-16 encodings.