docs/extensions/files.md

-# Extension files
-
-The [civix](./civix) command line tool will generate the following structure
-for you:
-
--   ***info.xml*** is a manifest that describes your extension – the
-    name, license, version number, etc. You should edit most information
-    in this file.
--   ***myextension.php*** stores source code for all your hooks. It
-    includes a few default hook implementations which will make
-    development easier. You can add and remove hooks as you wish. (Note:
-    This file name is different in each module – it is based the
-    module's *[short-name](./basics/#extension-names)*.)
--   ***myextension.civix.php*** contains auto-generated helper
-    functions. These deal with common problems like registering your
-    module in the template include-path. `civix` may automatically
-    overwrite this file, so generally do not edit it.
-
-In addition, it creates some empty directories. These directories are
-reminiscent of the directory structure in CiviCRM core:
-
--   ***CRM/Myextension/*** stores PHP class files. Classes in this
-    folder should be prefixed with "CRM\_Myextension\_"
--   ***templates/*** stores Smarty templates
--   ***xml/*** stores XML configuration files (such as URL routes)
--   ***build/*** stores exportable .zip files

docs/extensions/helptext.md

+# Adding pop-up help text in your extension
+
+In addition to simply adding help text for form fields that you have added in your extension as usual, you can also add to or replace help text for existing form fields in core. To do so, simply add a file in the same directory as the hlp file is found in core, with the name `helpfilename.extra.hlp`.
+
+If you want to append your help text to the existing text, add the htxt to your extra help file as normal. If you want to replace the existing text with your own text, add `override=1` to your htxt, for example: `{htxt id="field_name_id" override=1}...`. This works for both the content of the help text and the title.
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