of the project. Separate items with semicolons.
@item srclibs=a@@r;b@@r1;
-Specifies a list of source libraries (kept up to date using version control)
-from a predefined set. Separate items with semicolons, and each item is of
-the form name@@rev where name is the predefined source library name and rev is
-the revision in source control to use. You can then also use $$name$$ in the
-prebuild command to substitute the relative path to the library directory.
-
-The available source libraries are current hard-coded in common.py. This will
-later be data-driven.
+Specifies a list of source or Android libraries. Separate items with
+semicolons, and each item is of the form name@@rev where name is the predefined
+source library name and rev is the revision or tag in source control to use.
+Each srclib has a metadata file under srclibs/ in the repository directory,
+and the source code is stored in build/srclib/.
+
+Repo Type: and Repo: are specified in the same way as for apps; Subdir: can be
+a comma separated list, for when directories are renamed by upstream; Update
+Project: updates the projects in the working directory and one level down;
+Prepare: can be used for any kind of preparation: in particular if you need to
+update the project with a particular target. You can then also use $$name$$ in
+the init/prebuild/build command to substitute the relative path to the library
+directory, but it could need tweaking if you've changed into another directory.
@end table