Hey Simon,
Great job on the PR.
I like the implementation with (nested) ABC classes, I think it gives a lot of flexibility for different data types.
One thing that is not immediately clear for me with this implementation is how this implementation would "enforce" a standard way to store for example distance or speed data. For example, how would BaseFileHandler.to_df() always parse speed data in the same way? Or is the point that the implementation doesn't enforce that?

Hi Aert
This question kept me also awake for a couple of nights... But I think that the best way is that we create a class inhertited from the DataComponent called RecordData (maybe we should think about a more brother term like ActivityData or somthing) where we define how the data should look and thus also how we should parse the the data. The second options is that we even go further and create for every type of data (speed, power, etc...) a seprate component (and not store the entire ActivityData as a component it self ). so that the parse funciton is implemented in for example a SpeedData component but i don't know if this is needed.