This is a small request for enhancement for feature_label model layers.
Style currently support text-attribute with a named style. It would be great to add some sort of customisation to the output text, so more than one attribute can be shown, or a constant text (a symbol for example).
-keep "text-attribute:name" for basic labels and compatibility
-support "text-attributes:name1,name2,..." along with "text-attributes-format:format" with format a printf like syntax (or even simpler), and nameX the attributes to be used (list be may empty).
Does it make sense? Would it be a valuable contribution or is it too specific/complex to be included?
This is a good start, however I do think the embedded attribute needs to have a beginning and an end delimiter, whether is be the same character (like $name$) or brackets (like [name]). Personally I prefer the latter but that is just me. You are assuming that attribute names can only consist of alphabetic characters but I don't think we can impose that restriction.
The value string should support whitespace; if it doesn't, this is a bug.
BTW for submissions you can just attach the whole file or files using the More Options -> Upload File feature. Thanks.