Problem: SpecFlow feature files in VisualStudio 2019 for macOS don’t show up in the solution explorer. Rebuild, Unload, and Reload do not help. It just shows the generated .cs file but not the features file.

Solution: It turns out it is a common problem and people are still looking for the answer. This is the workaround I found and so far it is working for me.  Right-click the project > Display Options > Show All Files

After that, I am able to see my feature file.