The tendon as noted I have ony exeriemced as a feature in Vietnamese pho and sometimes in cold appetizers in Chinese restaurants Also in my cows foot soup. But yes not common in North America in my experiemce.
So all this nose to tail kept bringing uo to me pig bladder as a part of the pig slaughter celebration. Some in North America may recall the Laura Inglls Wilder description of kids delighting in blowing it up like a balloon and last night I watched one of the old Bourdain Cooks Tour in Portugal where they blew it up and played soccer. A French prep https://www.npr.org/2020/07/15/891290856/bill-buford-discusses-his-culinary-journey-in-new-memoir-dirt More local to me - the American South https://www.al.com/news/mobile/2018/02/post_133.html