In T170180#2408842, @Geez wrote:

Hello p4k1tz.
Due to the current priorities with the release and possible hotfix, we cannot address this immediately. I will let you know if there are any new developments.

@Geez Has this question been passed to anyone for a potential answer?

@Geez Any new information?

@Geez Any new information?

Above is an example response that can be used as a reference. Between offsets 0x0000002E and 0x00000032 should be the steam ID of the mod. But Offset 0x0000002D describes the steam ID length being 4 byes. 2E through 31 are not the correct steam ID, and neither is 2E through 32. I can only assume one of these bytes is a modifier for the steam ID, is corrupt, etc.

In T170180#2404850, @Geez wrote:

Hello again,

According to the devs:

https://developer.valvesoftware.com/wiki/Server_queries

It's just 1b header + long challenge, then some data if challenge is in incoming message - otherwise 1b header + int16 rules count and list of rules - which is as in steam documentation.

In T170180#2404740, @Geez wrote:

Hello p4k1tz.
Is there any relevant reason why do you need to know this information?

This is still an ongoing issue almost a year later, are there any updates or workarounds?