I found a webpage that lists many possible solutions to this question. I wonder, in such cases should I just post the link in comments, or write an answer summarizing the content with citation? I'd do the latter, but I concern if this is frowned upon on the site. Also, the webpage is easily found as it's the first result of googling "prevent apple browning".
Stack Exchange is meant to be more of an end-user publication than a list of links. The folks here will work hard to curate this collection of knowledge, so when someone finally finds this site through search, the last thing we want to do is send them elsewhere to find that information.
Add value by writing actual answers
Links sending users elsewhere to find that information aren't really considered an "answer" in the context of this this site. The goal is to try to add value to this site with your knowledge — links and citations are great as supplementary material, but relying on them heavily doesn't really add any value to the Internet.
And please do not post answers or links in comments. Comments do not have the features needed to properly vet whatever you say there, so answering in comments should almost certainly be flagged and removed. Links in comments are even worse. That only adds another barrier between the user and the actual information they are searching for — the information they expected to find here. It just sends users away to find the information themselves, and that's not what we do here.
Go to older SE sites and try to follow the links given in their old answers. Way too many links have moved or are dead now. Link-only answers in that stage are now truly useless.
Links are great: great for the internet, great for giving credit, point to way more info than is expected or feasible in one answer etc. We need them. But they die.
- cite and quote some central stuff (and give credit, do not plagiarise)
- paraphrase and summarise
At least the gist of the link target should be preserved in your answer here. And it has to be your own answer after all. Write an introduction, interpret what's at the link, draw your own conclusions.