Well, not entirely. When I first log in, a lot of the icon fonts still look ugly; changing them and changing back resolves it.
And uses of Liberation Sans Narrow in other apps (e. g. LibreOffice) still look ugly. I really need that particular font for one of my spreadsheets. rpm -V liberation-fonts doesn’t indicate any problems.
So the digging continues…
This appears to resolve all of the issues.
The most recent packages resolve the problems without need for the unofficial repo.
One quirk, though, is that if I select 7.5 point Liberation Sans Narrow in LibreOffice, I get 7.5 points with hinting turned off (i. e. it’s bigger than 7 point and smaller than 8 point). With slight hinting enabled, 7.5 point gets rounded up to 8 points. With Arial, I get the correct behavior. But I think that that’s unrelated to all of this.
In my case, this Plasma 5.10 update has introduced a lot of problems with fonts.
For example, Helvetica font-family is installed, enabled and available until Plasma 5.9; now, with Plasma 5.10, Helvetica is still installed but it does not appear in the font list.
Some font families look horrible, also with sub-pixel hinting enabled (GLDickens3 repo).
Kate editor, with Plasma 5.10, does not show keywords in bold when I use monospaced fonts.
For example, in an HTML document, Kate for Plasma 5.9 shows:
<title>xyz</title>
Kate for Plasma 5.10 shows:
<title>xyz</title>