I wanted this project also to encourage more and more PMC creators to work with structures/worldgen. Recently, Youtube creator WafflesAreBetter made awesome tutorials on How to make custom structures (Here's a link). I think he explains it far better than I could :). It's an awsome, broad topic, and there's already a wonderful legacy of people pushing it to its boundaries. This datapack, genrally speaking, lets any 3rd party datapack add new structures to the world, without modifying existing ones or risking to conflict with each other.

Here's how it works:
Each new structure can be implemented to the world without modifying the biome file. Instead, the engine has tons of pre-made configured_structure_features (placeholders) each for any structure type in any biome (except for rivers). For example:
"more_structures:village_birch_forest",
"more_structures:pillager_outpost_birch_forest",
"more_structures:bastion_remnant_birch_forest",
are the three lines inserted to birch_forest.json biome file. To override a certain placeholder, simply end structure's file setup on naming your configured_structure_feature as it's named in biome file (more_structures:<structure_type><biome>).
I don't feel really comfortable while explaining stuff, so feel free to ask me about anything.