Man pages matching name insighttoolkit in section 3:

insighttoolkit.3.en	debian 10 / libinsighttoolkit4-dev
insighttoolkit.3.en	debian 11 / libinsighttoolkit4-dev
insighttoolkit.3.en	debian 12 / libinsighttoolkit4-dev
insighttoolkit.3.en	debian 12 / libinsighttoolkit5-dev