@C_M , you have my sympathy, when I tried to understand Lensfun some time back, I found it impenetrable. The info above is the clearest I’ve seen about the two versions. thanks @ggbutcher and others!
How about you take up @paperdigits 's idea and explain how to do it for DT? I wrote this - How to build sigmoid and dt - some time back, to explain to non-tech people like me how to build DT. Simple steps, little prior knowledge assumed. If you covered Lensfun, that would be great. Eg pros and cons of installing versus building; how to build; how to use the conversion thing mentioned above, etc. I suggest do it for Ubuntu since I believe this is the most widely used linux flavour.