Key points are not available for this paper at this time.
A collection of 22 data set of 50+ requirements each, expressed as user stories. These were all found online, or retrieved from software companies with a permission to disclose. The data sets have been originally used to conduct experiments about ambiguity detection with the REVV-Light tool: https://github.com/RELabUU/revv-light
Fabiano Dalpiaz (Sat,) studied this question.