Man pages matching name x11::protocol::ext::double_buffer in section 3pm:

X11::Protocol::Ext::DOUBLE_BUFFER.3pm.en	debian 10 / libx11-protocol-other-perl
X11::Protocol::Ext::DOUBLE_BUFFER.3pm.en	debian 11 / libx11-protocol-other-perl
X11::Protocol::Ext::DOUBLE_BUFFER.3pm.en	debian 12 / libx11-protocol-other-perl