Hi Jim-
That is what is weird... There really is no evidence of frontal impact like I would think, buldging under the top tube as well, etc.
And the shape.. It isn't like a buldge but more like a big honking pimple!
It is circular in shape about .7mm in diameter... It is 9cm from the head tube on the under side of down- tube a little to the right (drive side).
No clue what it is...
Mike Wilkinson