Investigating the properties of stripped-envelope supernovae; what are the implications for their progenitors?

Supplementary data are available at MNRAS online.
\nFigre S1: (Top left) The spectra of SN 2016P without host emission
\nline removal. (Top right) Comparison with Ic-4 SNe 2002ap. The
\nlines of SN 2002ap are much broader and at higher velocity. (Lower
\nleft) Comparison with SN 1994I, the major features align, although
\nthe velocities of SN 1994I are typically higher (except for Na i D).
\n(Lower right) Comparison with Ic-7 SN 2007 gr. The velocities are
\nbroadly consistent but there are more features in the spectra SN
\n2007gr, albeit with a higher S/N
\nFigure S2: The spectra of SN 2013F, epochs are relative to
\nmaximum light.
\nFigure S3: Spectroscopic observations of SN 2013bb.
\nFigure S4: Spectroscopic observations of SN 2013ek.
\nFigure S5: Spectroscopic observations of SN 2015ah.
\nFigure S6: Spectroscopic observations of SN 2015ap.
\nFigure S7: Spectroscopic observations of SN 2016P.
\nFigure S8: Spectroscopic observations of SN 2016frp.
\nFigure S9: Spectroscopic observations of SN 2016iae.
\nFigure S10: Spectroscopic observations of SN 2016jdw.
\nFigure S11: Spectroscopic observations of SN 2017bgu.
\nFigure S12: Spectroscopic observations of SN 2017dcc.
\nFigure S13: Spectroscopic observations of SN 2017gpn.
\nFigure S14: Spectroscopic observations of SN 2017ifh.
\nFigure S15: Spectroscopic observations of SN 2017ixz.
\nFigure S16: Spectroscopic observations of SN 2018ie.
\nFigure S17: Spectroscopic observations of SN 2018cbz.
\nTable S1: 4000–10000 Å bolometric light curve properties of SNe
\nin the extended P16 sample.
\nTable S2: Derived E(B − V)host for SNe in P16 and updated
\nparameters
\nTable S3: Table of δm100 values for the extended P16 sample.
\nTable S4: Mej of the extended P16 sample SNe and comparison
\nwith Mej from spectral modelling and hydrodynamics codes.