`Expr` is listed in expressions and not statements.

[Former user]

The Expr type is a statement that's used to carry expressions.

[Thomas Kluyver]

You're technically correct (the best kind of correct), but it made sense to me to put it there. If it helps, think of the heading as 'these are the things you need to know about to work with expressions', not 'these are nodes of the expression type'. Technically, the operator tokens are not expressions either, while names and literals, which have separate sections, are expressions.