/usr/include/mediastreamer2/ is in libmediastreamer-dev 3.6.1-3.
This file is owned by root:root, with mode 0o755.
..
/usr/include/mediastreamer2/allfilters.h
/usr/include/mediastreamer2/bitratecontrol.h
/usr/include/mediastreamer2/dsptools.h
/usr/include/mediastreamer2/dtmfgen.h
/usr/include/mediastreamer2/ice.h
/usr/include/mediastreamer2/mediastream.h
/usr/include/mediastreamer2/msaudiomixer.h
/usr/include/mediastreamer2/mschanadapter.h
/usr/include/mediastreamer2/mscodecutils.h
/usr/include/mediastreamer2/mscommon.h
/usr/include/mediastreamer2/msconference.h
/usr/include/mediastreamer2/msequalizer.h
/usr/include/mediastreamer2/mseventqueue.h
/usr/include/mediastreamer2/msextdisplay.h
/usr/include/mediastreamer2/msfileplayer.h
/usr/include/mediastreamer2/msfilerec.h
/usr/include/mediastreamer2/msfilter.h
/usr/include/mediastreamer2/msinterfaces.h
/usr/include/mediastreamer2/msitc.h
/usr/include/mediastreamer2/msjava.h
/usr/include/mediastreamer2/msjpegwriter.h
/usr/include/mediastreamer2/msqueue.h
/usr/include/mediastreamer2/msrtp.h
/usr/include/mediastreamer2/mssndcard.h
/usr/include/mediastreamer2/mstee.h
/usr/include/mediastreamer2/msticker.h
/usr/include/mediastreamer2/mstonedetector.h
/usr/include/mediastreamer2/msv4l.h
/usr/include/mediastreamer2/msvideo.h
/usr/include/mediastreamer2/msvideoout.h
/usr/include/mediastreamer2/msvolume.h
/usr/include/mediastreamer2/mswebcam.h
/usr/include/mediastreamer2/qualityindicator.h
/usr/include/mediastreamer2/rfc3984.h
/usr/include/mediastreamer2/upnp_igd.h