Strips on the inside were likely added in the 20th century, likely to add a shelf. Sme missing glue blocks from underside of upper and lower steps.
High-res images are part of the condition report. Copy and Paste this Dropbox link into your internet browser to see high-resolution images: https://www.dropbox.com/scl/fo/p2otmkrf2epgd7l10t25z/AJjCOTT_m3u7tSO3RhF23ug?rlkey=dnhtms0vb0yll1roylm7m543o&st=5jclpz1u&dl=0