My question comes in two related parts: firstly, what is the piece of folded, drilled metal projecting rearwards from the lower bracket in the photo above?
Secondly, does this piece of metal have any significant implications for the suitability of this bicycle to have a mid-drive e-bike conversion kit installed?
This is a wider view of the bike. In order to address matters brought up in current answers, I should point out that I am this machine's first and only owner and rider, and it has spent most of its existence gathering dust in storage. It is around ten years old, and I doubt that I have ridden it more than around ten kilometers. It was very cheap, less than $200 Australian brand new from Big W.
I was considering installing a Bafang BBS or similar mid-drive kit.