Add developer blog about removing device filter from target selector (#2827)

Co-authored-by: Martin Hjelmare <[email protected]>

Author: emontnemery

blog/2025-10-14-device-filter-removed-from-target-selector.md

@@ -0,0 +1,23 @@
+---
+author: Erik Montnemery
+authorURL: https://github.com/emontnemery
+title: "Device filter has been removed from target selector"
+---
+
+The device filter option is no longer supported by the target selector and has been removed from the [target selector documentation](https://www.home-assistant.io/docs/blueprint/selectors/#target-selector).
+
+Hassfest has been updated to [fail on services with device filter on targets](https://github.com/home-assistant/core/pull/152794).
+
+Validation of target selectors that specify a device filter will fail in Home Assistant Core 2026.11.
+
+### Background
+
+Core helpers that extract entities from targets did not support the device filter. When the user picked a floor, area, label, or category, the filter was ignored. The frontend also ignored the device filter when selecting entities for a target.
+
+A review of all core integrations found no correct use of a device filter on target selectors. We removed the device filter from the target selector rather than implement support for it in Core and the frontend.
+
+### Impact on custom integrations and blueprints
+
+Update custom integrations and blueprints to remove device filters from target selectors.
+
+If you have a valid use case for device filters on target selectors, reach out on Discord.