The new icons on macOS result in a very ugly/funny/inconsistent looking tool bar in Linguist. It was not great before, but at least the icons had a similar style. Now it is a mix between minimalist flat, and colorful shadowed:

I'm also not sure I like the icon choice for "Open" and "Save all". IMO it would be nicer if these were somehow related, maybe with tray.and.arrow.up and tray.and.arrow.down . Or, another point would be that "Save all" doesn't look like saving multiple documents, so that could at least be square.and.arrow.down.on.square