Proof of concept for extension reserved indices

[cwperks]

Companion PR to cwperks/security#5

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: null ❌
• URL:
• CommitID: 0e7f23e
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: null ❌
• URL:
• CommitID: adc09c4
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: null ❌
• URL:
• CommitID: 8d1bcb0
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: null ❌
• URL:
• CommitID: 601a3d6
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?