I have part ownership of a house and acreage these days in rural southern Missouri. The house was built before the AHJ (county) adopted the NEC, so there are some quirks in the electrical system, one of them being the electrical panel (located in the master bath). Thankfully, the panel itself is a Square D QOC-16D Series L1 (and not some terrible piece of fire-protection-eliminating trash), but of course, it's underdocumented and stuffed to the gills with double-stuff breakers, including the two in the photo below in slots 11 and 15 in the panel that are of a style I have never seen before:
Did Square-D ever make a double-stuff QO with the handles in the configuration depicted, and if so, when? If not, who the heck made them? Are these oddly configured breakers obsolete in some way, compared to their more conventional double-stuff brethren (as exemplified by the QO2020 in slot 13 seen between them)?