The QoppaHerosNarrow family of font files was created by modifying the TexGyreHerosCondensed family of fonts.

TexGyreHerosCondensed is a font family part of the Tex Gyre Collection of Fonts maintained by the GUST project:
see https://www.gust.org.pl/projects/e-foundry/tex-gyre/index_html

The Tex Gyre fonts are licensed under the GUST font license, equivalent to the Latex Project Public License.
But note that QoppaHerosNarrow fonts are not released under that license but by the parent application's governing license.

All modifications to created the QoppaHerosNarrow fonts from the TexGyreHerosCondensed fonts were performed via FontForge.

The original TexGyreHerosCondensed font files used are included here in the file TexGyreHerosCn.zip for the sake of helping to ensure the terms of the GUST font license are satisfied.

Changes to TexGyreHerosCondensed fonts:
1. Changed internal font names to be consistent with QoppaHerosNarrow family name.
2. Changed copyright to Qoppa copyright.
3. Changed all Ascent/Descent related, underline, super/sub script metrics, OS/2 table entries, TeX metrics to be consistent with Arial Narrow
4. Converted outlines to TrueType outlines.
5. Changed version info