TCX

Training Center XML (TCX) is a data exchange format introduced in 2007 as part
of Garmin's Training Center product. The XML is similar to GPX since it
exchanges GPS tracks, but treats a track as an Activity rather than simply a
series of GPS points. TCX provides standards for transferring heart rate,
running cadence, bicycle cadence, calories in the detailed track. It also
provides summary data in the form of laps.

(https://en.wikipedia.org/wiki/training_center_xml): https://en.wikipedia.org/wiki/Training_Center_XML

TCX file format support is currently in beta status. Known limitations include

• no elevation compensation
• no time track extraction
• no handling of auxillary information