> I’m assuming they’re adding a trigger to the source table.

Their video demo for SQL Server simply points the command line at a connection string, and it then says 2 item(s) indexed. There wasn't a way to pick specific tables.

That means if the trigger method is true, they're adding a trigger by default to every single table in the database. That would be a remarkably bad idea.

The PostgreSQL one uses the logical replication feature, perhaps the MSSQL piece does something similar.