Man pages matching name tigetflag in section 3ncurses:

tigetflag.3ncurses.en	debian 10 / ncurses-doc
tigetflag.3ncurses.en	debian 11 / ncurses-doc
tigetflag.3ncurses.en	debian 12 / ncurses-doc
tigetflag.3ncurses.en	debian 13 / ncurses-doc