Fingerprinting committed in . It can be controlled with the [trac] fingerprint_resources option:
content: Calculate the fingerprint from the resource contents.
meta: Calculate the fingerprint from the resource metadata (size and mtime).
disable: Disable fingerprinting.
I have measured the time to calculate the fingerprint with the th:WikiExtrasPlugin installed, which is a bit of a worst case. On my machine, it takes 1.9 seconds when using the content, and 1.4 seconds when using the metadata. As this is only apparent during environment startup, I hesitate to even keep the "meta" option.
I will update the documentation with the new functionality, especially the part about serving static resources from the web server.