The pages in [this section] give some pointers about what syntax is allowed, but I cannot find a full reference. Is that available?
Alternatively, is there a parser for configuration files available in the Python SDK? I found [this example code] but when I use it to read a configuration file for my add-on/plugin/app ( service.confs["myconfigname"]), the result is just empty. A nonexistent name results in a KeyError, so by not raising an exception it confirms that it knows what I'm talking about but still refuses to return the sections ("stanza"s) and settings contained in that file. Looking at the source code, it doesn't actually read and parse the file but queries the API instead. Note that the setup page happily works with it, so Splunk can perfectly read the default values from the file and write to its local/ counterpart. A parser like splunklib.parseConf("myconfigname.conf") that reads the actual file would also solve the problem.