Dear Maintainer,
While running TRACE=1 licensecheck --lines 0 Documentation/50-pot/subsurface-user-manual.pot through the following file:
https://github.com/subsurface/subsurface/blob/master/Documentation/50-pot/subsurface-user-manual.pot
and searching for the query <License> false positives get shown. Some of the text gets recognised
as talking about Licenses and it attributes it to the wrong License (RealNetworks Public Source License 1.0) (you may find the output below).

scan for license fulltext
scan stepwise for license grant
located trait: licensed_under: 86-104 "distributed under "
located trait: licensed_under: 157584-157597 "according to "
located trait: licensed_under: 221007-221020 "according to "
located trait: licensed_under: 221391-221404 "according to "
located trait: licensed_under: 223879-223892 "according to "
located trait: licensed_under: 307336-307349 "according to "
located trait: name(rpsl): 223892-223900 "the real"
located trait: grant(rpsl): 223879-223900 "according to the real"
scan for oddities
scan for FSFUL fulltext
scan for FSFULLR fulltext
scan atomic for singleversion usage license grant
scan atomic for singleversion license grant
scan atomic for versioned license grant
collected some licensing: RPSL
scan atomic for misc fulltext/grant
resolved license expression: RPSL

Thank you for looking into this bug.