It seems that the devtools don't work with Apollo Client 3. After upgrading to Apollo 3.0.0-beta.23 I can no longer use the Apollo Devtools. The tab shows up and can be opened, but there is no content. Prior to this upgrade the devtools were hooked up and working.
"@apollo/client": "^3.0.0-beta.23",
"@apollo/link-batch-http": "^2.0.0-beta.3",
"@apollo/link-context": "^2.0.0-beta.3",
"@apollo/link-error": "^2.0.0-beta.3",
"apollo": "^2.24.0",
Chrome v. 80.0.3987.149
Have same issue with "@apollo/client": "^3.0.0-beta.37". apollo chrome tab is not active.
I just ran into the same issue.
Taking a quick look at the branches, it seems
https://github.com/apollographql/apollo-client-devtools/tree/release-3.0
might be 3.0 compatible.
I was able to get release-3.0 built and installed in Chrome, it looks like this:

The queries appear to be hard coded (not from my app). Seems it may still be too early to use.
@justinanastos, @cheapsteak not sure if you're still maintaining?
Would be appreciated if you could provide an update. Thanks for your work on this. 馃嵒
@bbrinx Thanks for opening this issue! Changes in the AC3 beta are incompatible with the current extension but we are working on a fix!
@onpaws I'll be leading on this project 馃榾Looking forward to getting you AC3-compatible devtools!
Glad to hear it @jcreighton! Good luck.
If memory serves I heard the Firefox extension was blocked by Mozilla for using eval, so if that's true, I especially wish you luck in that endeavour! :)
@jcreighton , that's great, thank you!! Could you give us some guidance when you expect to be able roll out an update of the devtools with AC3 support?
Most helpful comment
@bbrinx Thanks for opening this issue! Changes in the AC3 beta are incompatible with the current extension but we are working on a fix!
@onpaws I'll be leading on this project 馃榾Looking forward to getting you AC3-compatible devtools!