Excellent --- thanks for checking!
Okay, looks like this button:
should give you what you want, except for one minor problem --- I forgot to wire up the TSV to the button (in fact, the code accidentally doesn't save the data as TSV at all).
I have opened an issue here:
https://github.com/qiime2/q2-composition/issues/59
In the meantime, click the "View Source" button, then scroll down to "data" section (highlighted below):
This is the data you are looking for, in JSON format.
Sorry, stay tuned for a fix!