I don't think we *need* to have the encoding in the HTML calendar, but I doubt we could remove it at this point, deprecate maybe, but since I don't use the module I don't have a sense for how often the need for encoding comes up.

The one thing that the encoding is doing in the HTML calendar is ensuring that Unicode characters that are not directly translatable in the target encoding are replaced with html character references (the "xmlcharrefreplace" option to the errors argument in the encode method).

The encoding may be a holdover from Python 2x where the expected result was a string. The docs say HTMLCalendar was added in Python 2.5 at the same time that the Local versions were added.