Yes. They're normal here, and you can consider them about as significant as an import statement, some context when reading the code, but nothing crazy. The ex

Yes. They're normal here, and you can consider them about as significant as an import statement, some context when reading the code, but nothing crazy. The extensions are very well vetted, and new versions of the language standard can be summed up as "enable extensions a, b, c by default." Plus library changes, of course.