Approximate Search Results with Special Characters

We have some slightly strange behavior in the search bar in an Overview that I don’t understand. Some special characters appear to “activate” a more intensive approximate search match. For example:

Search Results Analysis
Bridge 43 matches Finds Bridge as a complete word
bRiDgE 43 matches Approximate search match appears to be on but not functioning as expected
Bridge* 61 matches The extra matches have Bridge as a substring, e.g. BridgeMaker, BRIDGECONSTRUCT,…

The Fields are marked with the appropriate “enable_approximate_match_search” annotation.

Is this to do with
mgmtp.a12.dataservices.search.analysis.full-text.escape-special-characters.enabled, see here? If so, is there any documentation what functionality the following special characters, + - && || ! ( ) { } [ ] ^ " ~ * ? : \, have?

Moin @malcolm-silver-ice,
these are Solr query terms, you can find detailed descriptions and explanations in their documentation.

E.g. the “*” is a wildcard search operator (see Wildcard Searches).

Kind regards,
Jan