How to open *.cap using C2fe?
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.cap format is used in Construct-Classic.
So your answer is it can't be done.
C2 (any edition) opens .caproj and .capx files.
You can't.
R0j0hound did create a simple conversion tool, but C2 has diverged far from CC now and as Ashley has pointed out in previous threads, it would be nearly impossible to do a full conversion due to differences in how plugins/behaviors etc are used.