diff --git a/share/man/man4/filemon.4 b/share/man/man4/filemon.4
index 441b00396d93..10f2a39c9051 100644
--- a/share/man/man4/filemon.4
+++ b/share/man/man4/filemon.4
@@ -64,6 +64,9 @@ to handle incremental builds more smartly.
 System calls are denoted using the following single letters:
 .Pp
 .Bl -tag -width indent -compact
+.It Ql A
+.Xr openat 2 .
+The next log entry may be lacking an absolute path or be inaccurate.
 .It Ql C
 .Xr chdir 2
 .It Ql D
@@ -82,9 +85,13 @@ System calls are denoted using the following single letters:
 .Xr rename 2
 .It Ql R
 .Xr open 2
+or
+.Xr openat 2
 for read
 .It Ql W
 .Xr open 2
+or
+.Xr openat 2
 for write
 .It Ql X
 .Xr _exit 2