Since the Unicode Consortium isn't going to actually assign those code points, this is functionally just a scheme for encoding variable-length integers designed

Since the Unicode Consortium isn't going to actually assign those code points, this is functionally just a scheme for encoding variable-length integers designed as an extension of UTF-8 more or less arbitrarily. There's a long history of designs for these (https://en.wikipedia.org/wiki/Variable-length_integer https://en.wikipedia.org/wiki/Variable-length_integer) that the author might be interested in. I used to think about these things myself, including the "zigzag encoding" for signed values (not a difficult idea; this "marvelous bijective mapping" is the standard one used in math class to demonstrate that the integers are countable, and the nice implementation properties are a consequence of the choice to "zig" from 0 to -1 first combined with how two's-complement works).