tcltk-man2html.tcl is used to build HTML documentation on Windows and other platforms. It attempts to include documentation for extensions/packages, but is limited to find packages under $tcldir/pkgs/ .
When building from repository checkouts (rather than the official Tcl source distribution) or building non-TEA compliant packages it is (in this developer's opinion) convenient to locate extensions adjacent to rather than under $tcldir.
To support this I suggest a command line option "--pkgdir" that can specify the directory under which package sources can be found, as an absolute or relative (to pwd) path. The default if "--pkgdir" is omitted is $tcldir/pkgs, retaining backwards compatibility.
Implementation is in the Fossil repo in branch frq-(this frq).