Exporting to ufo

I have a group of glyphs I do not want exported, and the Export box is unchecked. Yet when the file is exported to the ufo format, they are included in the resulting file. Considering they were not marked to export, I’m wondering if this is normal for the ufo export and if so, why?.

This (currently) applies only to binary font export, i.e., installable OpenType fonts like .otf, .ttf, .woff, etc. UFO is not a binary font export format. IIRC the current implementation was even a feature request way back, but I may be mistaken.