Man pages matching name gravitation in section 6:

Gravitation.6.en	debian 10 / gravitation
gravitation.6.en	debian 10 / gravitation
Gravitation.6.en	debian 11 / gravitation
gravitation.6.en	debian 11 / gravitation
Gravitation.6.en	debian 12 / gravitation
gravitation.6.en	debian 12 / gravitation