The California burrito is defined by the thing inside it that does not belong in a burrito: French fries. Carne asada, cheese, and guacamole go into a large flour tortilla, and instead of rice and beans the starch is a handful of fried potatoes rolled in alongside the meat. The tortilla is the engineering, not the filling: a flexible bread folded and sealed into a cylinder so a wet, loose, mixed load can be eaten standing up with one hand. The fries are what make this burrito its own sandwich rather than a generic one, and they are a structural choice as much as a flavor one.
As a sealed handheld it works because the build is arranged to survive being a closed tube. A burrito fails when the filling is too wet and blows out the seam, so the fries do double duty: they absorb the rendered juice from the carne asada and the moisture from the guacamole, keeping the interior dry enough to hold the fold while adding a soft starch and a crisp edge that rice would not. The carne asada is grilled and chopped small so the cylinder rolls tight and every bite is balanced rather than ending up all meat at one end. The cheese is added warm so it slumps and helps glue the fries and meat into a coherent mass instead of a slide of separate parts. The guacamole supplies the fat and acid that a heavy beef-and-potato core needs to not read as one dense note. It is wrapped tight, often in foil, so it holds heat and structure from the first bite to the last.
The California burrito sits in the American taco, burrito, and wrap family, a map of immigration where a flexible bread folds a complete meal into one hand. Its close relations stay in San Diego's idiom: the surf-and-turf build that adds shrimp, the carnitas or adobada swap, and the broader Mission-style burrito that manages moisture with rice and a foil wrap instead of fries. Those deserve their own articles rather than being crowded in here.