This procedure is defined in the server but not documented via ad_proc or proc_doc and may be intended as a private interface.
The procedure is defined as:
proc nsmcp::accessRetentionPhase {token phase unused} {
set key nsmcp:access-retention:[ns_info server]
set state [nsv_get $key state]
if {![dict get $state running] || [dict get $state token] ne $token} {return}
dict set state phase $phase
dict set state phaseTicks [clock clicks -milliseconds]
nsv_set $key state $state
}