The error messages are:
tbl_get_field.php: Missing parameter: where_clause
tbl_get_field.php: Missing parameter: transform_key
To reproduce: Create a table with an autoincrementing 'id' and a longblob 'picture', upload an image to 'picture', go to the Browse tab and click on the text similar to "[BLOB - 1.9 MiB]". The error text appears as an AJAX dialog.
According to my attempt at git bisect, the error message is a recent change but the expected behaviour has been silently broken since [db22f56fd2584508bc77cb03922020183ac8bb49] Document MaxRows behavior when a LIMIT clause is present...but that commit doesn't look suspicious at all, so I seem to have had some glitch when bisecting. At the very least I can at least report that QA_3_5 does not generate the error (it does want to download the .jpg as a .bin file instead, but I did not investigate that further); current master d359426f536303aa303d7bfcfbdbf430b2f87b97 gives the error message.