I don't think anyone would actually want to read the Math manual exported to LyXHTML but I want to make sure that this isn't a sign of an underlying bug. Exporting to LyXHTML is usually quicker than any of the pdf formats, but for the Math manual, it is about 10 times as slow (see the times below). I'm guessing that this is normal because of an expensive operation specific to exporting math to this format, but I just wanted to check.
$ ctest -R "doc/UserGuide" Test project /home/scott/lyxbuilds/master/CMakeBuild Start 124: export/doc/UserGuide_lyx16 1/5 Test #124: export/doc/UserGuide_lyx16 ....... Passed 3.40 sec Start 125: export/doc/UserGuide_xhtml 2/5 Test #125: export/doc/UserGuide_xhtml ....... Passed 3.06 sec Start 126: export/doc/UserGuide_pdf 3/5 Test #126: export/doc/UserGuide_pdf ......... Passed 12.90 sec Start 127: export/doc/UserGuide_pdf2 4/5 Test #127: export/doc/UserGuide_pdf2 ........ Passed 9.00 sec Start 128: export/doc/UserGuide_pdf5 5/5 Test #128: export/doc/UserGuide_pdf5 ........ Passed 13.87 sec $ ctest -R "doc/Additional" Test project /home/scott/lyxbuilds/master/CMakeBuild Start 54: export/doc/Additional_lyx16 1/5 Test #54: export/doc/Additional_lyx16 ...... Passed 2.15 sec Start 55: export/doc/Additional_xhtml 2/5 Test #55: export/doc/Additional_xhtml ...... Passed 2.08 sec Start 56: export/doc/Additional_pdf 3/5 Test #56: export/doc/Additional_pdf ........ Passed 6.87 sec Start 57: export/doc/Additional_pdf2 4/5 Test #57: export/doc/Additional_pdf2 ....... Passed 4.85 sec Start 58: export/doc/Additional_pdf5 5/5 Test #58: export/doc/Additional_pdf5 ....... Passed 11.10 sec $ ctest -R "doc/Custom" Test project /home/scott/lyxbuilds/master/CMakeBuild Start 59: export/doc/Customization_lyx16 1/5 Test #59: export/doc/Customization_lyx16 ... Passed 2.07 sec Start 60: export/doc/Customization_xhtml 2/5 Test #60: export/doc/Customization_xhtml ... Passed 1.49 sec Start 61: export/doc/Customization_pdf 3/5 Test #61: export/doc/Customization_pdf ..... Passed 4.72 sec Start 62: export/doc/Customization_pdf2 4/5 Test #62: export/doc/Customization_pdf2 .... Passed 3.60 sec Start 63: export/doc/Customization_pdf5 5/5 Test #63: export/doc/Customization_pdf5 .... Passed 8.84 sec $ ctest -R "doc/Math" Test project /home/scott/lyxbuilds/master/CMakeBuild Start 104: export/doc/Math_lyx16 1/5 Test #104: export/doc/Math_lyx16 ............ Passed 3.02 sec Start 105: export/doc/Math_xhtml 2/5 Test #105: export/doc/Math_xhtml ............ Passed 78.67 sec Start 106: export/doc/Math_pdf 3/5 Test #106: export/doc/Math_pdf .............. Passed 7.50 sec Start 107: export/doc/Math_pdf2 4/5 Test #107: export/doc/Math_pdf2 ............. Passed 6.59 sec Start 108: export/doc/Math_pdf5 5/5 Test #108: export/doc/Math_pdf5 ............. Passed 10.91 sec Thanks, Scott