I've noticed that the default setting for "Check document type" ("if unknown
(except /)"), combined with the default settings for MIME associations (none
specified, at least in the GUI), causes WinHTTrack 3.40 to MIME-check every
.htm page, temporarily saving the file with a .X.delayed extension,
determining that it is text/html, storing some internal cross-reference
between the .htm file and the .html file (in memory, I presume) and then
renaming it with an .html extension.

If I change "Check document type" to "never" and do an update, WinHTTrack 3.40
stores .htm files as .htm.

Is this behavior necessary as a default? Couldn't .htm be assumed to be
text/html just like .html is, as a default?