> But I didn't thought that a superfluous final blank line causes any problems. What software has a problem with it?

Currently I have not found a program that has problem with
the superfluous final blank line, and I think there won’t be.

> Removing the final blank line can harm the readability in the case of sequential writes to the same file

Sorry that I have not thought about this.
In this way, the prev patch that adds two new parameters might be better.

> Remind me, why do we care about that extra blank line?

Well, though it seems that that extra blank line won’t cause any problem,
it does not look nice I think, and is different with INI files written
by other applications.