Strange message: Firefox Android When I reopened Firefox after a few hours, it normally opens the last website I've viewed but it  displayed  for a second a strange message popup similar to
&quot;there is a more recent version of the page on the server, do you want to reload?&quot;, (maybe it's not 100% the exact phrase because of my translation and that I may have not read 100% correctly the popup).
I opened  Firefox about 4 hours before, then left Firefox in standby on the phone. Then I reopened the site without refreshing, when I saw notification above.
I have no malware on the smartphone, and it was just a normal website about cars.
What does the notification mean?
The message there is a more recent version of the page on the server, do you want to reload? is shown by the web site itself. It is generated via JavaScript and other web techniques and therefore can vary by size, displayed text and other properties.
When you re-open Firefox the previously cached web page is displayed.
Some web sites use special web techniques (JavaScript + WebSocket) to connect to the server in background and check for provided update information.
For example the Stackoverflow/Stackexchange web pages also use this technique for displaying an info header that new questions are available or that there is a new message in your &quot;inbox&quot;.

Therefore if your browser first loads the cached page and then checks for updates and displays this message. As the message is generated by the web page, not by the web browser itself it will only appear on web pages that use this technique and it may look totally different on each page.