diff --git a/ci/release/template/man/d2.1 b/ci/release/template/man/d2.1
index 1a5ebee02..42cead179 100644
--- a/ci/release/template/man/d2.1
+++ b/ci/release/template/man/d2.1
@@ -125,6 +125,9 @@ In watch mode, images used in icons are cached for subsequent compilations. This
 .It Fl -timeout Ar 120
 The maximum number of seconds that D2 runs for before timing out and exiting. When rendering a large diagram, it is recommended to increase this value
 .Ns .
+.It Fl -check Ar false
+Check that the specified files are formatted correctly
+.Ns .
 .It Fl h , -help
 Print usage information and exit
 .Ns .
@@ -180,6 +183,8 @@ See --font-semibold flag.
 See --animate-interval flag.
 .It Ev Sy D2_TIMEOUT
 See --timeout flag.
+.It Ev Sy D2_CHECK
+See --check flag.
 .El
 .Bl -tag -width Ds
 .It Ev Sy DEBUG