Usage of integer or integer range in mysql.user.host

I have been a mysql dba for a long time, yet I have never seen a user@host with an integer in the host column of the performance_schema.accounts table. In my case the user looks like this ‘dev_maint’@‘226567-60’. There are nearly 300 connections from this host. I can find nothing in mysql’s documentation on this usage. Could anyone please shed some light on this? It looks to be a host range, but how does one evaluate it?