Thanks for the feedback. Meanwhile I have seen that the value in a "key: value" pair can quite often contain an unspaced colon (URLs, IPv6 addresses, ...), which then gets colored with a red background. That was not the intention, so I have removed that regex fragment.
(When there is no space after the colon of a "key: value" pair, then the key will not get colored green. That should be enough indication that there is a syntax error. Coloring the unspaced colon red was in fact a double indication of an error.) I've also seen that for Yaml files related to Perl stuff, there can be keys that contain a double colon, so I've added that to the rules. Improved version of the syntax file (for older nanos) is attached. (I've also dropped the 'tabgives' command, as that probably doesn't work in your version of nano.) Benno
yaml.yaml
Description: application/yaml
OpenPGP_signature
Description: OpenPGP digital signature
