diff --git a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.use.mask b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.use.mask
index 66c01ec9ac..c02b3aba0d 100644
--- a/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.use.mask
+++ b/sdk_container/src/third_party/coreos-overlay/profiles/coreos/base/package.use.mask
@@ -27,3 +27,6 @@ sys-libs/glibc -crypt
 # We don't use pip.
 dev-lang/python ensurepip
 dev-lang/python-oem ensurepip
+
+# Pulls dev-python/sphinx, which in turn pulls a lot of other python stuff.
+sys-fs/btrfs-progs man