Lander (https://github.com/lsst-sqre/lander ) is currently hardcoded to produce landing pages with the old-style LSST branding. As part of updating our PDF landing pages to use Rubin Observatory branding (DM-25660) we want to generalize Lander with a plugin system so that the branding of the landing pages can be tweaked independently of Lander itself. This lets us ship separate documentation templates for different organizations (e.g. for Rubin operations vs Rubin construction).

The plugins should offer two categories of customization:

• Hooks to parse different types of LaTeX documents (i.e., Lander currently works with the lsstdoc class, but we could imagine also wanting to support aastex documents)
• Customized Jinja templates for HTML, along with customized CSS, JavaScript, and other assets.