I would like to ask you to change the character encoding of the MySQL databases for MediaWiki installations to utf8mb4 encoding. It looks like they currently use utf8 which means that it uses three Bytes to store a character. It is not a real UTF8 encoding, many characters can not be stored. This results in wiki pages being trimmed when someone enters a non-supported character [1]. There are currently two use cases which require "standard" UTF8 encoding.

• A user wants to write their OSM user name in the wiki. [1]
• A MediaWiki gadget is used and the internal UTF8 test fails, which renders it useless. [2]

Additionally, the current encoding is deprecated according to MySQL 8 documentation [3] and will be removed. The wiki currently uses MySQL 5.7.29.

[1] https://wiki.openstreetmap.org/w/index.php?title=Bot&diff=prev&oldid=1784135
[2] https://wiki.openstreetmap.org/wiki/MediaWiki:Gadget-HotCat.js
[3] https://dev.mysql.com/doc/refman/8.0/en/charset-unicode-sets.html