X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/8900e3ac8a8f610d4c1b3fbe7bdf4f0358efc28d..92c93a278036870a76740d5b0b8f06504925e7dc:/docs/usage_and_configuration/black_as_a_server.md

diff --git a/docs/usage_and_configuration/black_as_a_server.md b/docs/usage_and_configuration/black_as_a_server.md
index fc9d1ca..a2d4252 100644
--- a/docs/usage_and_configuration/black_as_a_server.md
+++ b/docs/usage_and_configuration/black_as_a_server.md
@@ -54,8 +54,11 @@ The headers controlling how source code is formatted are:
   command line flag. If present and its value is not the empty string, no string
   normalization will be performed.
 - `X-Skip-Magic-Trailing-Comma`: corresponds to the `--skip-magic-trailing-comma`
-  command line flag. If present and its value is not the empty string, trailing commas
+  command line flag. If present and its value is not an empty string, trailing commas
   will not be used as a reason to split lines.
+- `X-Preview`: corresponds to the `--preview` command line flag. If present and its
+  value is not an empty string, experimental and potentially disruptive style changes
+  will be used.
 - `X-Fast-Or-Safe`: if set to `fast`, `blackd` will act as _Black_ does when passed the
   `--fast` command line flag.
 - `X-Python-Variant`: if set to `pyi`, `blackd` will act as _Black_ does when passed the