In T165100#2314202, @Marcin648 wrote:

I found undocumented config variables to enabled a2s (steam query)

	"a2sQueryEnabled": true,

Query port can also be change by undocumented variable

	"steamQueryPort": 17777,

In T165100#2313005, @barf wrote:

AFAIK it doesn't need or use the steam query port, the server browser works over HTTP/REST

Server with no port 17777 listening here shows up in server browser OK

I confirm that netstat shows no signs of port 17777 and the server doesn't show up in steam browser.