Here's what the guys at Alby say:
One option is to create a new namespace or expand the existing one. However, an alternative approach could be to leverage the RSS namespace extension for podcasting, which already includes the necessary tags. For instance, the value tag can be used to define the payment method and recipient, while the new medium tag allows for easy differentiation of content types, such as "blogpost", "newsletter", "video", or "music", as specified values. This approach streamlines the implementation process, utilizing existing infrastructure and established standards.
Maybe something like:
<podcast:value type="lightning" method="address" suggested="0.00000006900"> <podcast:valueRecipient name="ejzys" type="address" split="95" address="ekzyis