Run a text search on all SMBC comics. The underlying database is a SQLite database built by scraping the SMBC website and running easyocr optical character recognition (OCR) on each comic. This was preformed by a complete OCR newb (me), so the text has a lot of errors. Still, if I don't say myself, search works suprising well.
If you see a match but nothing is highlighted in the comic transcript snippet, the search was probably matched to the mouseover text.