[Serif font] Regular and salt italic J glyphs should be swapped

[iacchi]

First of all, thank you for keeping this font alive, it really is my favourite!

This said, it's from the Libertine time that this font has (according to me, but I'm not alone looking at the internet) one big issue: the italic J. The regular italic J just looks weird and out of place, while the salt version looks like normal (other salt characters look kind of weird as well in general, but that's fine, because they are a variant). Just to make it clear, e.g. in latex (compiling with xelatex) this is the output of J \textit{J} $J$ \addfontfeatures{Style=Alternate}{\textit{J}} \addfontfeatures{Style=Alternate}{J}:

As you can see, the regular J is fine, while the salted regular J looks fancy/weird, which is fine. The math mode italic J also looks fine, as it should be. However, you can see that the regular italic J looks similar to the salted regular J, while the salted italic J looks similar to the regular J.

Here lies the problem, especially if you want to write scientific texts, and especially if like me you work with electricity, and therefore you use italic J (symbol for current density) a lot. At least with xelatex you can use the \addfontfeatures{Style=Alternate}{} command to type a normal-looking italic J, but pdflatex for example can't do this, and regardless it's i) cumbersome to do all the time, ii) breaks the word, so new line behaviour when it happens can be odd, and iii) this doesn't help with referencing with bibtex anyway, as you can't manually edit the J (well, you can in the bib file, but that's going to take you ages) in there, and of course there are a lot of Journals that you need to cite in a work, and they all end up just looking weird.

Due to all this, would it be possible to fix this, and swap the glyphs for the regular and salted italic J? Apart from the aforementioned issues, I think that that's where they both belong anyway, so I would consider this an actual bug.