Will Safari eventually support the full declarativeNetRequest API?

Goal

To migrate a small Safari extension from the legacy .safariextz format to a Safari Web Extension while keeping user experience continuous.

Constraints

The migration must avoid downtime, so the new extension can coexist with the old one until users update. However, a key API needed for content blocking—declarativeNetRequest—is only partially supported in Safari 17, and its future completeness is unclear. The rule limit (5,000 static rules) is already a bottleneck for complex filter lists.

Unresolved Decision

It is not yet documented whether Safari will implement the full declarativeNetRequest specification as defined by the WebExtensions community, nor when such an implementation might appear.

Questions

• Will Safari eventually support the full declarativeNetRequest API?
• When can developers expect a complete implementation, if at all?
• How will rule limits and partial support impact extensions that rely on large or dynamic filter lists?