While small (16px*16px) and large (24px*24px) has already support, Sifr missing extra large localization support (B,I,U, etc), please add them.
Step to reproduce:
1. Change icon to Sifr with size extra large
Rizal Muttaqin committed a patch related to this issue.
It has been pushed to "libreoffice-6-4":
Sifr: Fix for tdf#131566: Add extra large localized icons
It will be available in 6.4.4.
The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.