The hgrc is the primary configuration file of a Mercurial repository. It may sometimes be useful to document some of its contents with comments.
The hgrc file follows the INI file format. In the INI file format, a line beginning with a semicolon (;) character is a comment line. So, this can be used in a hgrc file to write comments.
Some software that read INI files also allow the hash (#) character to begin a line of comments. Mercurial supports this too in the hgrc file as a comment line.
Tried with: Mercurial 2.2.2 on Windows 7 64-bit