Wrapping code

[Charlie]

Maybe you could phrase that the other way around, and suggest a scenario where it doesn't work?

While the manual doesn't say a lot about how to use the line extension character, from experience you need to extend from an operator and not just anywhere in the line.
For example:
myvariable31 = myvariable1 + myvariable2 + myvariable3 +_
myvariable4 + myvariable5
should work.

However;
myvariable31 = myvariable1 + myvariable2 + myvar_
iable3 + myvariable4 + myvariable5
will not.

It's called a line extension, but it's really statement extension to include terms and operators on the following line. You can't just jam it anywhere in the line of text and have the next line pick up exactly where the first left off.