[Plugin: RSS Footer] Execute PHP-Code inside RSS Footer?

One year ago there was the question to execute php code inside rss footer [1]. I’d like to bring this topic up again. Would it be possible to add this function? It would be great to add additional dynamic content to the footer. I could use it for example to put a dynamic flattr thing into the footer [2].

Thanks for all your great work!
Christoph

[1] https://www.ads-software.com/support/topic/php-code-into-rss-footer?replies=3
[2] https://www.ads-software.com/support/topic/remove-flattr-button-from-rssatom-feed?replies=11#post-1978697