diff --git a/packages/grafana-e2e-selectors/src/selectors/README.md b/packages/grafana-e2e-selectors/src/selectors/README.md
index 35ceebd326d..ef419dac1fa 100644
--- a/packages/grafana-e2e-selectors/src/selectors/README.md
+++ b/packages/grafana-e2e-selectors/src/selectors/README.md
@@ -17,6 +17,7 @@ const components = {
 A few things to keep in mind:
 
 - Strive to use e2e selector for all components in grafana/ui.
+- Don't ever delete selectors. Even though a selector may not be used in the Grafana repository, it can still be used in external plugins.
 - Only create new selector in case you're creating a new piece of UI. If you're changing an existing piece of UI that already has a selector defined, you need to keep using that selector. Otherwise you might break plugin end-to-end tests.
 - Prefer using string selectors in favour of function selectors. The purpose of the selectors is to provide a canonical way to select elements.
   `pages.Dashboard.url('ud73s9')` is fine.