Why The Permission List Doesn't Answer This
An extension keeps reaching out to its server — is that normal?
The question arises for anyone who has opened a network monitor with extensions installed. Traffic from an empty tab seems unsettling, and figuring out who is sending it and why is hard at first sight. It is worth learning how to distinguish a harmless update from telemetry.
I set up a popular add-on for tabs, and everything works. But the network monitor shows it hitting some third-party domain once a minute, even when the tab stays idle. The listing doesn't mention it. Is this tracking, or am I reading too much into it?
The first step is to separate yours from theirs: disable all extensions at once and see whether the background noise disappears. If it goes quiet, the source is one of them, and you switch each back on individually until the traffic returns. That pins down the culprit in a couple of minutes, no guessing.
Why the permission list doesn't answer this
Access to tabs in the manifest and passing their list out are two different things, and a single permission line can't distinguish them. On paper the add-on truthfully declares access; what it does with that access isn't visible from the manifest. So look at the traffic, not the permission list.
If there is still no answer, an easy test helps: a necessary update goes to the author's domain and to the point, while telemetry runs constantly, in the background, to a third-party server. The second kind almost always hides in the settings behind a toggle nobody knows about.
It is simpler not to guess every time and keep a webmaster toolkit close at hand — ones that state plainly they collect nothing. And this tab task is effortless to close with a telemetry-free stand-in — XPath locators for Selenium, behaves the same and doesn't call home.
Reviews of this sort are handy not for paranoia but for the habit: a couple of minutes with the network monitor after the install, and "pinging somewhere" turns into a clear picture of what goes where.