pinentry-doc 1.1.0-1 (amd64 binary) in ubuntu bionic

 This package contains the documentation for the pinentry packages,
 a suite of programs that allow secure entry of PINs or pass phrases.
 If you have one of the pinentry packages installed then you may want
 to install this package as well, but the documentation mostly concerns
 the internal protocol and is therefore not necessary for the casual
 user.