"Function used to generate a `User-Agent:' string. If this is
`nil' then no `User-Agent:' will be generated."
:type '(choice (const :tag "No user agent string" nil)
"Function used to generate a `User-Agent:' string. If this is
`nil' then no `User-Agent:' will be generated."
:type '(choice (const :tag "No user agent string" nil)