How to get the Timecodes of footage used by a sequence, similar to an EDL's values?

I am developing a plugin that shall generate a text file for the purpose of documenting the _used_ footage. It's for a media design company that needs to know which and how much "foreign" footage it used.

For this purpose, the plugin needs to learn the actually used range of frames, or their TCs, of the footage that's references in a sequence.

How do I get to that information?

I know how to learn of the original footage tracks, but I have a hard time determining the TCs, especially if the footage is embedded into the sequence at a non-trivial time scale. For instances, if it's using  speed-ramp, I cannot simply take the TCs from the track, as they do not directly translate into the range that they're taken from the footage (1s of play time in slo-mo) may mean that it's 10s in the footage - and that's the timing I need in order to know how much needs to be credited to the original footage.

When I export a sequence to EDL, then these TCs are right there, though! This means that there's code in Premiere that can calculate these values. The question is simply how I get to them from a plugin.