Remove "[Signature]" from popup

Hi there,

First of all; thanks for the plugin. I needed this very quickly, and expected that I’d would ‘waste’ my weekend on puting something simple together. Very neat plugin!

My only question; (how) can I remove [Signature] from the popup with the info on the petititon (see image). I can’t find where this text originates, help would be very welcome.

Kind regards.

Image: https://www.dropbox.com/s/uoyg5p71qhe9z9t/signature.PNG

https://www.ads-software.com/extend/plugins/speakup-email-petitions/