I’ve added labels to the upload and preview buttons as well as the toolbar toggle.
https://github.com/discourse/discourse/commit/13c9d7e70431c91d03e206e2f04121bc8cb69db7
@Matt_Campbell You’re right about the benefits of using existing text where possible, but I ended up adding two new strings so the label can say “[Show/hide] composer toolbar”. I considered using “options,” but it didn’t seem descriptive enough, especially considering that the button is a toggle.