diff --git a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
index b4fc64e753..bc08c814d1 100644
--- a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
+++ b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-metadata.xml
@@ -1929,6 +1929,38 @@
not careful.
+ [number_threads]:
+ Limits tasks to a specific number of simultaneous threads
+ during execution.
+ This varflag is useful when your build host has a large number
+ of cores but certain tasks need to be rate-limited due to various
+ kinds of resource constraints (e.g. to avoid network throttling).
+ number_threads works similarly to the
+ BB_NUMBER_THREADS
+ variable but is task-specific.
+
+ Set the value globally.
+ For example, the following makes sure the
+ do_fetch task uses no more than two
+ simultaneous execution threads:
+
+ do_fetch[number_threads] = "2"
+
+ Warnings
+
+
+ Setting the varflag in individual recipes rather
+ than globally can result in unpredictable behavior.
+
+
+ Setting the varflag to a value greater than the
+ value used in the BB_NUMBER_THREADS
+ variable causes number_threads
+ to have no effect.
+
+
+
+ [postfuncs]:
List of functions to call after the completion of the task.