https://rws-ammunition.com/fileadmin/user_upload/rws/Bilder/Seiten/Service/Downloadbereich/Weitere%20Downloads/Flyer/Englisch/Flyer_RWS_10_3x68-Mag-Smart-Magnum_ENG.pdf
Nothing new about it
RWS 10.3 x 68 (https://www.all4shooters.com/en/hunting/ammunition/rws-speed-tip-professional-bullet-new-caliber-magnum/)
It is a BELTED case for which you will need a longer Magnum action
Germans caught the American fever for new cartridges !
It might not be new, but very few people have heard of it. Just passing on info so that you can sound very clever around the campfire when some smart aleck tries to stump you with this calibre.
I can not find much about it, being a new design has no real history.World of Cartridges has very few 10.3 mm bullet mentions,and no 10.3 x 68.
I'd imagine that the task of making a truly 'new' cartridge would be daunting. Making one that does something that no existing one does perfectly adequately must be terrifying unless you are looking to exploit some arbitrary legal loophole like the need for straight walled cartridges for hunting in some states in the US or having a service pistol/rifle that doesn't use a military cartridge like has been needed in some parts of Europe before.