Unable to find the REL_16_STABLE version

Dear Team'

There is an SOC alert to create an extension set_user from the following URL https://github.com/pgaudit/set_user/archive/refs/heads/REL_16_STABLE.tar.gz however when try access the above URL getting 404 server Not Found error. So when checked in the pgaudit/ser_user/release found only REL4_0_1 and REL4_1_0RC1 only. So please advise how the REL_16_STABLE version urgently. 