One thing to fix: for 'fossil commit' there should be some hook to convert a file after it leaves EDITOR and before it get into Fossil database. EDITOR (a program with command line got from 'EDITOR' environment variable) most often using default 8-bit console charset (for Cyrillic it is 'Windows-1251' under Windows and 'KOI8-R' under Unix), but in the Fossil repo there is 'UTF-8' encoding. When I do commit with a Cyrillic (Russian) text in comment, Fossil put it into db w/o conversion (as Windows-1251), and when displaing it in UTF-8 UI it becomes unreadable. So it should be hook for convertor or some internal option or command line for iconv.

Something like these GIT's options (from .gitconfig):

[i18n]
	commitencoding = windows-1251
	logoutputencoding = cp866