SharePoint 2019 feature id and feature list you can find out using powershell. You will understand basic powershell commands related to Get-SPFeature so as to get sharepoint feature id details and features related ot this sharepoint feature id. Follow step by step procesure to find out how to get sharepoint 2019 features id and features.
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We can get all webs and site templates under site collection by using the a small script. Read full article to know in details.