bitbake: bitbake-user-manual: details about variable flags starting with underscore

Fixes [YOCTO #14140]

(Bitbake rev: 0f3e9d87168813ce49995ff04bccdce11c5f7b47)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst
index b533d9dc0e..b7c3d8091f 100644
--- a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst
+++ b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.rst
@@ -422,6 +422,12 @@ documentation to a BitBake variable as follows::
 
    CACHE[doc] = "The directory holding the cache of the metadata."
 
+.. note::
+
+   Variable flag names starting with an underscore (``_``) character
+   are allowed but are ignored by ``d.getVarFlags("VAR")``
+   in Python code. Such flag names are used internally by BitBake.
+
 Inline Python Variable Expansion
 --------------------------------