Is there a means to handle response headers with a Content-Disposition recommended filename, so that filename can be used or later /renamed? eg, http://example.com/get?100 -> somefile.mp3

Nope. $urlget() allows you to specify no dir/filename, a dir, a filename, or a dir + filename. In all cases, it will either use the dir/filename you specify or will determine these itself from your DCC folders, the URL path, the redirect path, etc. If resume is not used, it will add an incrementing number to the filename if it already exists. For example: //echo result: $urlget(https://www.mirc.com/get.php,gf,,alias).

Update: there is an issue where making repeated calls to the above non-resume $urlget() results in some calls failing due to identical filenames being used. Fixing this required moving the non-resume filename check to a different point in the download. This change will be in the next version.