split column

let
    Source = Web.Page(Web.Contents("https://www.nyse.com/markets/hours-calendars")),
    Data0 = Source{0}[Data],
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(Data0, {"Holiday"}, "Attribute", "Value"),
    #"Replaced Value" = Table.ReplaceValue(#"Unpivoted Other Columns","*","",Replacer.ReplaceText,{"Value"}),
    #"Extracted Text Before Delimiter" = Table.TransformColumns(#"Replaced Value", {{"Value", each Text.BeforeDelimiter(_, "("), type text}}),
    #"Merged Columns" = Table.CombineColumns(#"Extracted Text Before Delimiter",{"Attribute", "Value"},Combiner.CombineTextByDelimiter(" ", QuoteStyle.None),"Merged"),
    #"Changed Type" = Table.TransformColumnTypes(#"Merged Columns",{{"Merged", type date}})
in
    #"Changed Type"

Hi Syndicate_Admin 

You can put the following code to advanced editor 

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("dZLBbsIwDEB/xeppq9AEZVA4bkNMY8BlSGhiHFJqkWiQICdl6m2/sd/blyy0dCppuFTVs/0cO1mtgjl+wTsy+v3+0TBiedAKZkqmLG/BhMmMUQ4dy5aYStQNvOAZuXTdWgUzRkZImGaGI8GrkFubQXfXGvQ8MGr7MoeFfsk0t06j5EfWbkexhkdBhqcX9jEmVBX5aOyl/aLBs1IpjEmUxvKnBXaqDYdoWEMPBxI76AwaqFvuAfeKBNs5g8+YnS92Qd8FvcIxySQaRGk4zJkRSlrdi0zxgPYjN3h212/IVpRT1+7nn1XnrMiph8dXL93lcB9elHpJF25cEahEIx0xvS36TFmiyFnGGx4M7hP7TiIv7XhpXPgWnMlPvRVH+xoa556r49k7CMMrkfhqpG8jpxZPnIQ2e6abex7h5pzcCx1PI1Qtygms138=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Holiday = _t, #"2024" = _t, #"2025" = _t, #"2026" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Holiday", type text}, {"2024", type text}, {"2025", type text}, {"2026", type text}}),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Changed Type", {"Holiday"}, "Attribute", "Value"),
    #"Replaced Value" = Table.ReplaceValue(#"Unpivoted Other Columns","*","",Replacer.ReplaceText,{"Value"}),
    #"Added Custom" = Table.AddColumn(#"Replaced Value", "Custom", each Text.BeforeDelimiter([Value],"(")),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Value"}),
    #"Duplicated Column" = Table.DuplicateColumn(#"Removed Columns", "Attribute", "Year"),
    #"Merged Columns" = Table.CombineColumns(#"Duplicated Column",{"Custom", "Attribute"},Combiner.CombineTextByDelimiter(",", QuoteStyle.None),"Date"),
    #"Changed Type1" = Table.TransformColumnTypes(#"Merged Columns",{{"Date", type date}, {"Year", Int64.Type}})
in
    #"Changed Type1"

Output

Best Regards!

Yolo Zhu

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

Same result, different approach:

let
    Source = Web.Page(Web.Contents("https://www.nyse.com/markets/hours-calendars")),
    Data0 = Source{0}[Data],
    YearsColNames = List.Buffer(List.RemoveNulls(List.Transform(Table.ColumnNames(Data0), each try Number.From(_) otherwise null))),
    StepBack = Data0,
    TransformToDates = Table.TransformColumns(StepBack,
     List.Transform(YearsColNames, (colName)=>
        { Text.From(colName), each Date.FromText(Text.From(colName) & ", " & Text.Trim(Text.BeforeDelimiter(Text.TrimEnd(_, {"*"}),"(")) , [Format="yyyy, dddd, MMMM %d", Culture = "en-US"]), type date })),
    UnpivotedOtherColumns = Table.UnpivotOtherColumns(TransformToDates, {"Holiday"}, "Year", "Date")
in
    UnpivotedOtherColumns