Translated from en-US locale.
I'm going to suggest that scriptish.properties file property:
options.enabledSchemes.unmht=unmht protocol (Mozilla Archive format)
should include .mht format in the description
Also, as the extension can be used on Seamonkey, and maybe in future versions on other browsers, to replace all "Firefox" references in the locales (in en-US at first, and if replaceable not being Firefox specific) with a neutral "browser" reference.
Translation of the new properties, change of one ALT key to avoid overlapping, and one minor letter case change.
Is there any problem with this pull request for not being merged?
@strel looks like this needs to be updated, sorry for the bit rot