Power Query (Get & Transform) uses the M language to allow you to customise and build in flexibility to your queries.
Currently writing the M language is tricky to write. It is case sensitive and there is no built-in help to assist you using the language.
Apparently Microsoft is working on creating an M editor, but there is no time line on when it will be ready.
This article takes you through some steps to create your own editor using Notepad ++.
If you use Power Query a lot then this may be worthwhile.
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