let
Source = Table.Transpose(Excel.CurrentWorkbook(){[Name="Données"]}[Content]),
#"Grouped Rows" = Table.Group(Source, {"Column1"}, {{"Count", each Text.Combine(List.Distinct(List.Transform(_[Column2],Text.From)),", ")}}),
Count = Table.AddColumn(#"Grouped Rows", "Custom", each List.Count(Text.PositionOf([Count], ", ",Occurrence.All))+1),
#"Split Column by Delimiter" = Table.SplitColumn(#"Grouped Rows", "Count", Splitter.SplitTextByDelimiter(", ", QuoteStyle.Csv), List.Transform({1..List.Max(Count[Custom])}, each "Item" & Text.From(_))),
#"Promoted Headers" = Table.PromoteHeaders(Table.Transpose(#"Split Column by Delimiter"), [PromoteAllScalars=true])
in
#"Promoted Headers"