Man pages matching name msymbol_is_managing_key in section 3m17n:

msymbol_is_managing_key.3m17n.en	debian 10 / m17n-docs
msymbol_is_managing_key.3m17n.en	debian 11 / m17n-docs
msymbol_is_managing_key.3m17n.en	debian 12 / m17n-docs