:group 'gnus-article-buttons
:type 'regexp)
-(defcustom gnus-button-valid-fqdn-regexp "\\([-A-Za-z0-9]+\\.\\a)+[A-Za-z]+"
+(defcustom gnus-button-valid-fqdn-regexp "\\([-A-Za-z0-9]+\\.\\)+[A-Za-z]+"
"Regular expression that matches a valid FQDN."
:version "25.2"
:group 'gnus-article-buttons