Most tools I know of only support the latter (2001) namespace form, which may be why the W3C decided to go back to it, but they did sow a bit of confusion with this namespace change and reversal.

据我了解，多数工具只支持后一种(2001)名称空间形式，这可能是W3C决定回到原来的名称空间的原因，但这种名称空间的变化和撤销确实带来了一些混乱。

youdao