Answer: The most likely meaning of this phrase is "reveal yourself"
Step-by-step explanation:
The meaning of the verb 'to unfold' is 'to reveal.' This verb was frequently used by Shakespeare in his plays. In Act I, Scene I of Hamlet, we have one more instance of this verb:
"Pity me not, but lend thy serious hearing
To what I shall unfold. "
This line is uttered by the ghost of Hamlet's father, which tells Hamlet not to pity it, but listen to what it is about to reveal.
In the excerpt given above, Francisco is asking the other speaker (Bernardo) to 'reveal himself.'