A http(s) interface to custom url scheme.
Let's say you have a custom url scheme that Notion refuses to accept:
x-devonthink-item://870E7555-1953-45D6-B143-B2D857F8FD0C
Now, append it with x.zenan.ch/ so that it becomes:
x.zenan.ch/x-devonthink-item://870E7555-1953-45D6-B143-B2D857F8FD0C
This link will work with Notion and it will redirect you to x-devonthink-item://870E7555-1953-45D6-B143-B2D857F8FD0C.
Allowing custom url scheme to work cross-platform on notion.so.