I think it would register no recognition to the majority of American English speakers. It is a French loan word used essentially only in open source contexts because we don't have an equivilent ("free" is way more ambiguous is meaning).
The only negative connotation I know of is the association with some overzealous nerdy kids who find out the difference between libre and gratis and loudly bring it up all the time.
Italy here. "Libre" sounds spanish to me. I realized only now that french has the same word (and I read it many times), but probably the final e is silent. I pronounce it, so it's spanish. Apparently it's the correct way: https://lwn.net/Articles/408141/
When I first saw LibreOffice I first thought it was a take on the comedy movie Nacho Libre. And I studied French, so you'd think that would help but not really.
Though the French pronunciation differs as the IPA shows /libʀ/ which is rather different than spanish /ˈliβɾe/. So its one of those "final e is silent, with a french twist" words that were maddening to learn after German where that almost never happens.
I don't no much French but I think in this case the final e is not silent but also not stressed. Stress is on the i, same as in the Spanish pronunciation I think.
The only negative connotation I know of is the association with some overzealous nerdy kids who find out the difference between libre and gratis and loudly bring it up all the time.