Other browsers also respect this and there's nothing in the spec to
suggest this shouldn't happen. I removed the border since it was
inconsistently drawn only on missing images with alt text.
Other browsers do not have this at all.
Previously, the `preload`, `preconnect` and `dns-prefetch` keywords
took precedence over the others. When these keywords were present
the default fetch processing steps would not occur even when a relevant
keyword such as `stylesheet` or `icon` was present.
