Here’s a slightly edited version of the first email.
Today, contributions rely on an integration between AMO and Paypal, which requires frequent maintenance and has broken multiple times in the last few years. We want to remove this integration, and give you the ability to enter a contributions URL of your choosing. The Contributions button on your listing page would then open a new tab with that URL, rather than open a Paypal popup.
For security reasons, the contributions URL will be restricted to a predetermined set of payment processors. Paypal and Patreon are the obvious initial choices, but we want to hear from you about other payment services you would like to use. Please add your suggestions to this forum thread.