What is the meaning of 0 B value in the Size column?
On the right (see screenshot) we can see there was content, so why does the Size column say zero?
In some other request is shows (correctly, I would say) a non-zero value.
Screenshot link (not embedded, as it is a bit too wide): https://i.imgur.com/OX8cgC3.png
This is on Firefox 62.0 64 bit on Windows.