When adding html files to calibre (portable 1.28 on Windows), as new ebooks. then converting them to azw3 to edit them. calibre adds many tags. (such as "<calibre p> <calibre class 1> <calibre class 2>".)

is there a way not to have "calibre" tags" added.
or is there a guide as to when calibre will insert each tag so i can properly create/edit my css file? (if it's in the calibre guide please tell me were)