Microsoft Excel Macro (.xlm)
The XLM file extension stands for "Excel Macro", a format used in early versions of Microsoft Excel to store macro instructions. Introduced with Excel 4.0 in the early 1990s, XLM files enabled automation of repetitive tasks by recording sequences of actions performed within the spreadsheet. They were pivotal in the evolution of Excel's macro capabilities, which later transitioned to VBA (Visual Basic for Applications). While XLM is largely obsolete now, understanding its role is crucial for grasping the history of Excel's automation features.