(En passant: I tried \info BarLine but could not see "extra-spacing-width". See the attached debug)
But in general, I think it's not a good idea to dump these kind of doc infos as the output of a library, for several reasons.
First of all because it has limitations in formatting and in linking between different pages. The resulting output is therefore too long to read.
I think it's enough to make some adjustments to the current output of the autodoc tool.
First one would be to add, with small fonts, at the bottom of the page, a list of the pairs (as links): class/interface - overriden/implemented property, inside an expandible panel (hidden by default).
In this way, IF I can't find an useful property in the main panel, THEN I can look at the implemented interfaces list at the bottom. At this point, if in this (short) list there's a name that looks interesting, I click on it without expanding the below panel, and I jump to the linked page. If I can't guess the right interface, I would expand the below panel and I would look more accurately in the contained (long) list. This avoids to jump forth and back from page to page.
In general, I see this as a good default choice for the autodoc of libraries, but even if it's not set as default, the command to produce a complete autodoc should be documented as well. In this library (which I made some years ago and could not update, in the last years)
you can find a directory for the autodoc (Doxygen) and the instructions to build it. Then, it is left to the user how much complete or minimal the autodoc has to be.
Best,
P