Add review guidance for deprecated components

.github/instructions/acl-deprecated.instructions.md

@@ -0,0 +1,15 @@
+---
+description: "Review guidance for changes to the deprecated ACL execution provider and its eventual removal."
+applyTo: "onnxruntime/core/providers/acl/**,include/onnxruntime/core/providers/acl/**,cmake/onnxruntime_providers_acl.cmake"
+---
+
+# Deprecated ACL Execution Provider
+
+The ACL EP is deprecated and will be removed in a future release.
+
+## Review Policy
+
+Report changes that expand or prolong the deprecated ACL EP surface and require explicit maintainer justification
+that the scope is appropriate.
+
+Accept changes that directly remove code or enable removal.

.github/instructions/jsep-deprecated.instructions.md

@@ -0,0 +1,24 @@
+---
+description: "Review guidance for changes to the deprecated JSEP implementation and its removal or migration."
+applyTo: "onnxruntime/core/providers/js/**,onnxruntime/contrib_ops/js/**,js/web/lib/wasm/jsep/**,onnxruntime/wasm/pre-jsep.js,cmake/onnxruntime_providers_js.cmake,js/build_jsep.bat"
+---
+
+# Deprecated JSEP
+
+JSEP is deprecated and is being replaced by the native WebGPU EP. Follow the contribution policy in
+[`docs/JSEP_Deprecation.md`](../../docs/JSEP_Deprecation.md), which is the authoritative source for its status and
+accepted changes.
+
+## Review Policy
+
+Report new operators, features, or performance-only work as actionable findings and direct that work to the native
+WebGPU EP in `onnxruntime/core/providers/webgpu/` or `onnxruntime/contrib_ops/webgpu/`.
+
+Accept correctness and security fixes to existing behavior. Require focused regression coverage for an accepted JSEP
+fix.
+
+For a JSEP WebGPU kernel fix, inspect the corresponding native WebGPU EP implementation. Report an actionable finding
+if the same defect applies there but the change does not include the native fix and focused regression coverage.
+
+Accept deprecation, migration, or removal work. Read and follow
+[`docs/design/onnxruntime_web_jsep_to_webgpu_ep_migration.md`](../../docs/design/onnxruntime_web_jsep_to_webgpu_ep_migration.md).

.github/instructions/webgl-deprecated.instructions.md

@@ -0,0 +1,19 @@
+---
+description: "Review guidance for maintenance and removal of the deprecated onnxruntime-web WebGL backend."
+applyTo: "js/web/lib/onnxjs/backends/webgl/**,js/web/lib/onnxjs/backends/backend-webgl.ts,js/web/lib/backend-onnxjs.ts,js/web/test/unittests/backends/webgl/**,js/web/test/e2e/browser-test-webgl.js,js/web/script/generate-webgl-operator-md.ts,js/web/docs/webgl-operators.md"
+---
+
+# Deprecated WebGL Backend
+
+The onnxruntime-web WebGL backend is deprecated and scheduled for removal.
+
+## Review Policy
+
+Report changes that expand the WebGL backend with new operators, features, or performance work. Direct new GPU work
+to WebGPU and users who cannot use WebGPU to the WASM/CPU backend.
+
+Accept correctness and security fixes to existing behavior. Require focused regression coverage for an accepted WebGL
+backend fix.
+
+Accept deprecation and removal work. Read and follow
+[`docs/design/onnxruntime_web_remove_webgl_backend.md`](../../docs/design/onnxruntime_web_remove_webgl_backend.md).

docs/JSEP_Deprecation.md

@@ -17,6 +17,9 @@ JSEP is in maintenance mode: **bug fixes and security fixes only.**
 | New operator | The native WebGPU EP — `onnxruntime/core/providers/webgpu/` or `onnxruntime/contrib_ops/webgpu/` |
 | New feature, or performance work | The native WebGPU EP |
 
+For a correctness or security fix to a JSEP WebGPU kernel, check the corresponding native WebGPU EP implementation
+and include the equivalent fix and regression coverage when the same defect applies.
+
 Note that [`js/web/docs/webgpu-operators.md`](../js/web/docs/webgpu-operators.md) lists **JSEP** operators despite
 its name, so it cannot be used to check what the native WebGPU EP already covers.