Following the Joni upgrade in #47374 the following warning is printed on Elasticsearch startup:

regular expression has redundant nested repeat operator + /%\{(?<name>(?<pattern>[A-z0-9]+)(?::(?<subname>[[:alnum:]@\[\]_:.-]+))?)(?:=(?<definition>(?:(?:[^{}]+|\.+)+)+))?\}/

I guess it means there is a non-fatal inefficiency in this regex:

That regular expression has not changed for a long time, so fixing it is probably not necessary for correctness, but it will avoid questions on forums/issues/support cases if it could be fixed before release of 7.5.