Instead of having the long description in the module manifest, it's possible to have a separate description file. Since version 8.0, it can be replaced by a README file, with either a .txt, .rst, or an .md (Markdown) extension. Otherwise, include a description/index.html file in the module.

This HTML description will override the description that's defined in the manifest file.

There are a few more keys that are frequently used:

• licence: The default value is LGPL-3. This identifier is used for licence under the module that is made available. Other licence possibilities include AGPL-3, Odoo Proprietary License v1.0 (mostly used in paid apps), and Other OSI Approved Licence.
• application: If this is True, the module is listed as an application. Usually, this is used for the central module of a functional area.
• auto_install: If this is True, it indicates that this is a glue module, which is automatically installed when all of its dependencies are installed.
• installable: If this is True (the default value), it indicates that the module is available for installation.
• external_dependencies: Some Odoo modules internally use Python/bin libraries. If your modules are using such libraries, you need to put them here. This will stop users from installing the module if the listed modules are not installed on the host machine.
• {pre_init, post_init, uninstall}_hook: This is a Python function hook that's called during installation/uninstallation. For a more detailed example, refer to Chapter 9, Advanced Server-side Development Techniques.