Riapro

I have been transferred over today to Squarespace from Google Domains, and I am now trying to confirm everything is set up correctly and won't cause errors in the future. However I'm confused by what I see on the DNS interface under "Email Forwarding" - it references a third party website I've never used and which I can't find any indication is connected or used by Squarespace for this, specifically Mailgun.
Does anyone know if this is the norm for Squarespace domains using Email forwarding, or a hangover from Google Domains email forwarding?
Host                                                Type    Priority         Data @
                                            MX
      10
        mxa.mailgun.org
@
                                           MX
        10
        mxb.mailgun.org
@
                                           TXT
        0
         v=spf1 include:mailgun.org ~all
 
smtp._domainkey
           TXT
0
< A big long string of alphanumeric>