I've been using K-Meleon for quite some time now.
(since version 1.5.4)
When I upgraded to version 75.1, my bookmarked favicons
disappeared when I cleared the HISTORY data.
I experimented several times to ensure that it was HISTORY
and not CACHE, COOKIES, etc.
It looks as though favicons are stored in the
"places.sqlite" file.
And clicking either...
Tools>Privacy>Clear Data>Clear History
or
Tools>Privacy>Clear Data>Clear All
or
Tools>Privacy>Clear Data>Clear Automatically...
(and putting checkmarks in the History selections)
it ERASES everything in the "moz_favicons" table
that's within the "places.sqlite" file.
Is this a Gecko problem or K-Meleon problem?
If it's a Gecko problem (and can not be fixed) ...
my suggestion is to stored favicons like Google Chrome.
Here is an excerpt from an exported bookmark file
that Chrome created...
"
https://translate.google.com/" ADD_DATE="1440284532" ICON="data:image/png;base64,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">Google Translate
{note: html link coding is not allowed in the forum, so I removed that part}
As you can see... Chrome apparently converts ALL favicons to
a PNG format and stores it in a bookamrk file.
(so that they are univerisally acceptable and always available?)
If it's a K-Meleon problem...
maybe there's a way to clear everything from "places.sqlite"
EXCEPT the "moz_favicons" table?
Or... maybe... store favicons like the example above (from Chrome)
in the bookmark file?
T.I.A.,
BigD