I understood it as: They don't want the low barrier to entry that "one-click let me hack this in the browser" a la Github enables.* E.g. they are not actively s

I understood it as: They don't want the low barrier to entry that "one-click let me hack this in the browser" a la Github enables.* E.g. they are not actively seeking to increase the number of contributors. (*) Which is awesome for many/most projects. But there a valid reasons not to want it.