Library Size
All the functions and the base class in the library are minimalist by design and only contains what is needed for their purpose.
The main export (with WebComponent + html) is 1.7 kB (min + gzip) according to bundlephobia.com, and the WebComponent base class is 1.96 kB (min + brotli) according to size-limit.
Every change that moves this number is recorded in size-change-log.md, with the reason the bytes were spent and the benefit they bought.