I did mean sudo pacman -Syu yes but I was getting package not found. Not nothing at all… weird.
Have you tried updating your mirrors?
yay and/or sudo pacman -Syu
He has yes but using the welcome app. He should use what @UncleSpellbinder suggested as we don’t know what he specified in relector-simple which I assume he used.
Oh, ok you’re serious about having to go full -Syu … unfortunately that’s a whole other affair for me (including having to update certain drivers than fail to play nicely with kernel updates on my desktop).
Will come back to this when I have more time.
Meanwhile, it’s not like it won’t install. It’s as if it doesn’t exist in the extra repo as far as I can see … even after updating mirrors, rebooting. Very strange.
FWIW, I just tried @UncleSpellbinder’s
reflector --protocol https --verbose --latest 25 --sort rate | sudo tee /etc/pacman.d/mirrorlist
… just for good measure. Same outcome. No response to sudo pacman -Ss librewolf
Will go for full system update later on and report back.
Then how are you keeping your EOS up-to-date??
I’ve had weird lag start up issues in Librewolf and Firefox before which I fixed by creating a new profile.
Besides… I used to keep a backup of the profile folder till one version change I was told I couldn’t use that profile on a new version so stopped relying on that. (this was many versions ago I admit).
I reallllly hope they keep this package updated and it stays in Extra. I’ve missed LW so much! I’ve been using Brave-origin and it’s just not been the same.
Not to take this off-topic, but I love Brave Origin. It’s now my default browser with Librewolf as my secondary browser.
If you haven’t synced to the latest repo databases (-Sy) then you’re using the old database - you need to sync to see the librewolf package, which was recently added to the repos.
Do not run -Sy without realizing that if you install any package after doing so but before perfoming a full update (with -u, as in -Syu) you will be in a partial upgrade state.
EXACTLY. Partial upgrades can really screw up any Arch or Arch-based system.
Off Topic:
Summary
I wonder if he’s talking about Nvidia 580. I don’t know what other drivers would leave him unable to update the system as a whole and there’s enough info on this very forum to get the AUR package up and running.
installed it with just > sudo pacman -S librewolf <
Thanks to all for your suggestions thus far.
Nope. No NVIDIA cards in either this desktop or the laptop.
Actually, it’s the audio sound driver in a 2019 iMac that refuses to function without compiling a separate driver … and that driver then wants renewed vows of love and attention after any kernel update.
Separately, re: librewolf installation, am not interested in adding another AUR package; only extra repo packages at this time.
Meanwhile, am doing a full -Syu update on the laptop and will try again and report back. (Have never done a partial -Sy and don’t plan to start now 
)
UPDATE: Success. After a full system update, reboot: the librewolf package in the extra repo has been found and is installating.
I’ve had many times when I tried to add (or update) a package without performing a -Syu update and have gotten failed installation attempts. Oftentimes, simply updating mirrors does the trick.
But I’ve never experienced the apparent absence of an existing repo package. Not acknowledging that it’s there at all. Live and learn!
Thanks again to everyone for all the solid guidance. 
Please refer to my reply to you above. If you don’t perform a Sync then you are using old databases - which point to old package versions. If a package has been recently added to the repos, you will not see it until you run a Sync.
But you should never run a Sync without also performing a full update.
Thanks. Makes sense on one level.
But from a practical standpoint, a full system update is not something I typically do when checking out a single (new to me) package. Perhaps I really should… but this becomes a PITA on my finicky daily driver iMac hardware. Less so on other installations around the house. Alas.
On a rolling distro that gets upstream updates all the time it is recommended to always use -Syu when installing something to avoid getting into “dependecy hell”