Bug report – KDE Plasma 6 / xdg-desktop-portal-kde

## Title

`xdg-open fails to open local files with Wine applications (App info not found for 'org.kde.')`

---

## Product

**KDE Plasma**

## Component

**xdg-desktop-portal-kde**

## Version

* Plasma: **6.x (Fedora 43 KDE Spin)**
* Frameworks: **KF6**
* Qt: **6.x**

---

## Platform

Fedora Linux 43 (x86_64)
Session: KDE Plasma 6 (Wayland and X11 tested)

---

## Description

When using **Wine applications installed system-wide (non-Flatpak)** and properly registered with a valid `.desktop` file (including `MimeType=application/pdf`), `xdg-open` fails to open local files and returns a portal error.

This occurs even though:

* the application appears correctly in the KDE menu
* the application works when launched directly
* file associations work via Dolphin (double-click)

---

## Steps to Reproduce

1. Install a Windows application using Wine (example: PDFgear).
2. Create a valid desktop entry in:

   ```
   ~/.local/share/applications/pdfgear-wine.desktop
   ```

   Example:

   ```ini
   [Desktop Entry]
   Name=PDFgear (Wine)
   Exec=env WINEPREFIX=/home/user/.wine wine "C:\\Program Files\\PDFgear\\PDFgear.exe" %f
   Type=Application
   MimeType=application/pdf;
   Icon=application-pdf
   ```
3. Update KDE cache:

   ```bash
   kbuildsycoca6
   ```
4. Run:

   ```bash
   xdg-open test.pdf
   ```

---

## Actual Result

The following error is returned:

```
qt.qpa.services: Failed to register with host portal
QDBusError("org.freedesktop.portal.Error.Failed", "Could not register app ID: App info not found for 'org.kde.'")
```

Then `xdg-open` attempts to open:

```
http://test.pdf/
```

---

## Expected Result

`xdg-open test.pdf` should open the file with the associated Wine application, just like:

* double-clicking the file in Dolphin
* using “Open With” in KDE

This behavior worked correctly in **Plasma 5**.

---

## Additional Information

* The issue does **not** appear to be related to Wine configuration.
* The same Wine application launches and opens files correctly when:

  * started from the KDE menu
  * started directly via `wine app.exe file.pdf`
* `gio open test.pdf` works correctly.
* This suggests a **portal-kde AppID detection issue** for non-Flatpak applications (Wine).

---

## Workarounds

* Use `gio open file.pdf` instead of `xdg-open`
* Open files directly from Dolphin
* Set default applications via KDE System Settings

---

## Regression

Yes.
This behavior worked correctly under **KDE Plasma 5**.

---

## Severity

Normal

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## Notes for maintainers

Wine applications do not provide a DBus AppID. Plasma 6 / xdg-desktop-portal-kde appears to **require a resolvable AppID**, causing `xdg-open` to fail even when a valid `.desktop` file and MIME association exist.

This likely affects **all Wine-based applications** on Plasma 6.

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