RFC 3875, "The Common Gateway Interface (CGI) Version 1.1", October 2004Source of RFC: INDEPENDENT
Errata ID: 5266
Publication Format(s) : TEXT
Reported By: Denny O'Breham
Date Reported: 2018-02-25
Section 4.1.17 says:
SERVER_SOFTWARE = 1*( product | comment )
It should say:
SERVER_SOFTWARE = 1*( *( SP | HT ) ( product | comment ) )
It seems actual usage separates products and comments with spaces such as «Apache/2.4.27 (Win32) OpenSSL/1.1.0f PHP/7.1.9». The definition «1*rule» in section 2.1 doesn't include implicit optional (required?) spaces as a separator.
The proposed definition is backward compatible with the original.