diff --git a/documentation/ref-manual/ref-structure.xml b/documentation/ref-manual/ref-structure.xml
index 6912d3f6b2..541a47e556 100644
--- a/documentation/ref-manual/ref-structure.xml
+++ b/documentation/ref-manual/ref-structure.xml
@@ -660,9 +660,21 @@
build/tmp/cache/
- When BitBake parses the metadata, it creates a cache file of the result that can
- be used when subsequently running commands.
- BitBake stores these results here on a per-machine basis.
+ When BitBake parses the metadata (recipes and configuration files),
+ it caches the results in build/tmp/cache/
+ to speed up future builds.
+ The results are stored on a per-machine basis.
+
+
+
+ During subsequent builds, BitBake checks each recipe (together
+ with, for example, any files included or appended to it) to see
+ if they have been modified.
+ Changes can be detected, for example, through file modification
+ time (mtime) changes and hashing of file contents.
+ If no changes to the file are detected, then the parsed result
+ stored in the cache is reused.
+ If the file has changed, it is reparsed.