Hello,
in my use case I'm using mailpit in dev environment just changing the app SMTP configuration from production one, so mail recipients are real addresses that I don't want to send mails when debugging.

I need to release mails to my mailbox to double check the result, so basically every time I need to override the mail address inserted into release function. It would be helpful to have it automatically populated.

I'll leave it up to you to choose the best approach, taking into account any other scenarios you may be aware of.
Personally, the following come to mind:

• Adding another parameter
• Use the mailbox of MP_SMTP_RELAY_ALLOWED_RECIPIENTS if it's set to a single mail address
• Save the last used mail address somewhere in the browser (cookie, session, etc..) if it has been override from the original one

Thank you very much for the platform, it's really useful and almost perfect!