SE4 plugin from LADSPA pack?

The one included doesn’t have Gain expansion (dB)? It acts as all other SCx compressors.

Am I overseeing something?

SE4 is a third party plug-in, and I agree it appears to be broken.

You could try contacting Steve Harris as he is officially the maintainer of the “Steve Harris” plug-in collection, though these plug-ins are all rather old and I don’t know to what extent he is still maintaining them.

Can you PM any instructions?

Try going here Issues · swh/ladspa · GitHub , sign up then press the “New Issue” button on that page.