but again, I never used Ardour (or any audio DAW) but I thought idea of locked/protected tracks still common there? At very minimum it gives you more fine control about editing...

That has been the problem here -- not having used Ardour, not sure of all of the details but it was programmed here with what could be done (modifying a program that was originally designed so many years ago when computers were still living in caves).

note, my implementation of hidden preference actually done in localsession, too, just like gang_mode itself.

Also I think this line has a typo (ares instead of are) ?

"More details ares described next about master tracks"

Thanks for pointing this out as every little bit helps. I fixed it and checked it into GIT (finally something I know how to do!)

Finally, is there a way to numerate chapters in html output? ( so reference to numbered chapter can be easily found by browser's search function.)

Not sure if this is possible, but latex2html has a lot of possible options. My concern would be that it would change the html actual name which would create the problem of the Alt/h hotkey no longer working. If possible, I could create another version on the website just for this purpose. Sometimes it is easier to use the PDF version but that probably will not work on Android.