Yes. In Preferences > Add-ons > Blend Inspector, you can set file size warning/critical thresholds, max texture resolution, packed image size limits, and toggle individual scene health checks.

Under 1 second for most files. Very heavy scenes (1000+ objects with complex modifier stacks) may take a few seconds for the evaluated mesh analysis.

The analysis covers local data only. Linked library data blocks are excluded from the report since they're managed by their source files.

Yes, Ctrl+Z works immediately after purging. However, once you save the file after purging, the removed data is gone permanently.

They show uncompressed GPU memory (width x height x channels x bit depth). Actual VRAM depends on your GPU driver and render engine, but the estimates are reliable for comparing relative impact.

No. The inspection is completely read-only. The only actions that modify data are the explicit fix buttons (Purge, Fix Transforms, Fix Unused Slots), and each requires a deliberate click.