I think it is quite important to say that the $Matches hashtable will only contain the first occurence of the matching pattern.
It is not so obvious, there are no examples regarding this fact and it is not clearly stated.

Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: 5a1473a9-d19e-26f6-6a90-13d802f0ed35
• Version Independent ID: ac918b8d-aece-5c59-2a88-64c1a91ff5f5
• Content: about_Regular_Expressions
• Content Source: reference/6/Microsoft.PowerShell.Core/About/about_Regular_Expressions.md
• Product: powershell
• GitHub Login: @SteveL-MSFT
• Microsoft Alias: slee