Man pages matching name text::context::eitherside in section 3pm:

Text::Context::EitherSide.3pm.en	debian 10 / libtext-context-eitherside-perl
Text::Context::EitherSide.3pm.en	debian 11 / libtext-context-eitherside-perl
Text::Context::EitherSide.3pm.en	debian 12 / libtext-context-eitherside-perl