What's Changed
* Finetune Stylelint configuration by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2270
* Allow the `html_lang` Jinja2 filter to accept and pass through plain strings by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2271
* Add translations to the demo project by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2272
* Fix a bug where maps would be shown even no places would be available by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2274
* Add missing declarations of the Maps and Trees extensions' assets directory paths by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2273
* Add Weblate as a sponsor by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2275
* Extract functionality into an internal theme API by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2276
* Improve and expand the installation documentation by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2277
* Document Weblate by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2278
* Fix a bug where File pages would not show images for PDFs by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2279
* Extract functionality into an internal search API by bartfeenstra in https://github.com/bartfeenstra/betty/pull/2280
**Full Changelog**: https://github.com/bartfeenstra/betty/compare/0.4.2...0.4.3