Does Arduino IDE 2.x automatically expire its package index cache after a set interval?

Cache behavior in Arduino IDE

The Arduino IDE (both 1.8.x and 2.x) caches package_index.json and library_index.json locally under the Arduino15 directory, reusing them until manually deleted or refreshed via the Board Manager's "Update Index" action. There is no documented time-to-live (TTL) for these caches, nor does the GUI expose a "Clear Cache" button; users must locate and delete the cache files manually, which varies by operating system.

Observed symptoms of stale cache

• Board Manager shows outdated board package versions
• Library Manager lists obsolete library versions
• Signature verification failures when upstream metadata changes
• "Library not found" errors after successful installation

The CLI provides arduino-cli core update-index and arduino-cli lib update-index to force a refresh, but these are not discoverable from the IDE. Third-party board managers (e.g., ESP32, STM32) host their own package indexes with independent update cadences, and corporate HTTP proxies may add another caching layer.

Open questions

1. Does the IDE or CLI implement any automatic cache expiry (e.g., a 24-hour TTL) for package_index.json or library_index.json?
2. Is there a planned GUI action to clear all caches without manual filesystem access?
3. Do the HTTP requests for package indexes use ETag or If-Modified-Since headers to support conditional GET and cache-busting?