The "/help" page:

Show the built-in help text for CMD. CMD can be a command-line interface command or a page name from the web interface or a setting. Query parameters:

name=CMD

Show help for CMD where CMD is a command name or webpage name or setting name.

plaintext

Show the help within <pre>...</pre>, as if it were displayed using the "fossil help" command.

raw

Show the raw help text without any formatting. (Used for debugging.)