Minimal reproduction: https://github.com/marcustyphoon/orion-ios-extension-test/tree/json-fetch
Fetching the result of runtime.getURL() allows web extensions' content scripts to access data files included in their package (if they're matched by the web_accessible_resources manifest key). This works just fine in desktop Orion, but while runtime.getURL() is supported on iOS Orion as documented, the fetch itself seems to fail with "TypeError: Load failed."
(This causes XKit Rewritten to not load on iOS Orion.)
Like desktop Orion does, iOS Orion should allow extensions to fetch web_accessible_resources in content scripts.
1.3.6 (2) (WebKit 8617.1.17.10.9)
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