For 2.6 a new admin setting type (admin_setting_php_extension_enabled) was introduced by MDL-42671. It allows to show a warning when some optional extension is not installed in the server and some feature may require it. It's a special setting, without storage in DB and friends, just informative.

The setting uses the central format_admin_setting() function to display its HTML. Unluckily that function does not allow to "hide" some parts of the output that have not sense for this setting, namely:

• the default value information.
• the label (and name) of the setting (aka, left "column").

So this is about to consider which of these solutions is better:

1. Add 1 extra param to the function to instruct it to skip rendering defaults and labels.
2. Modify the special setting to use another, reduced, function, say "format_informative_setting()" or so.
3. Hard-code the rendering into admin_setting_php_extension_enabled->output_html() and don't use any core function.

That is, ciao