Evidence: GLOW accessibility audit of psy101-gradebook.xlsx
Score: 54 out of 100. Findings: 15.
Checked by GLOW (letitglow.app), which applies the same rules every time.

HIGH     XLSX-BLANK-COLUMN-HEADER  (7)
         Column 2 header is blank.
HIGH     XLSX-TITLE  (1)
         Workbook title is not set in document properties.
MEDIUM   XLSX-COLOR-ONLY  (1)
         4 empty cell(s) with background color may convey meaning through color alone.
MEDIUM   XLSX-MERGED-CELLS  (3)
         Merged range A1:F1 disrupts screen reader navigation.
MEDIUM   XLSX-SHEET-NAME  (2)
         Worksheet tab 'Sheet' has a default/generic name.
LOW      ACB-EMPTY-TABLE-CELL  (1)
         31 empty cells in the data region. Consider using a dash or N/A.

What this report cannot see: anything a person has to judge, such as
whether alt text is meaningful, whether color carries meaning, or
whether the order of information makes sense. Ask a person.