I think this comment was copy-pasted as is from the comment some lines below, but this is about hibernation, not sleep.
Ok? Index: acpibtn.c =================================================================== RCS file: /cvs/src/sys/dev/acpi/acpibtn.c,v retrieving revision 1.44 diff -u -p -u -p -r1.44 acpibtn.c --- acpibtn.c 2 Mar 2017 10:38:10 -0000 1.44 +++ acpibtn.c 11 May 2017 11:10:21 -0000 @@ -236,7 +236,7 @@ acpibtn_notify(struct aml_node *node, in goto sleep; #ifdef HIBERNATE case 2: - /* Request to go to sleep */ + /* Request hibernation */ if (acpi_record_event(sc->sc_acpi, APM_USER_HIBERNATE_REQ)) acpi_addtask(sc->sc_acpi, acpi_sleep_task, sc->sc_acpi, ACPI_SLEEP_HIBERNATE);