"Jarred salsa" refers to salsa (a spicy sauce typically made with tomatoes, onions, and chili peppers) that is packaged and sold in a jar or a similar container. Full definition
Also, because this salsa is blended, there won't be any of those big chunks of cooked tomato that are often found in jarred salsas. (e2bakesbrooklyn.com)
I made several changes to their recipe, including subbing cubed red potatoes for russets and using a can of diced tomatoes with green chile in place of jarred salsa. (wendyweekendgourmet.com)