diff --git a/xdsgui/README.md b/xdsgui/README.md
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--- /dev/null
+++ b/xdsgui/README.md
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+# xdsgui
+
+Graphical user interface for XDS data processing: visualizes control
+images and statistics, helps with writing XDS.INP.
+
+- Upstream: https://wiki.uni-konstanz.de/xds/index.php/XDSGUI
+- License: free of charge (see upstream)
+
+## How it is built
+
+Upstream ships a prebuilt, unversioned Linux binary at a fixed URL, so
+the module version is the download date. `pbuild::install` wgets
+`xdsgui` and the `generate_XDS.INP` helper script from
+https://wiki.uni-konstanz.de/pub/linux_bin/ into `$PREFIX/bin` and
+marks them executable.
+
+Loading the module puts `$PREFIX/bin` on `PATH` and auto-loads the
+runtime dependencies `H5ToXds/1.1.0`, `xds/20260616` and
+`autoPROC/20240710` (xdsgui calls xds and the helper tools).
+
+## Verifying the install
+
+```sh
+module use MX unstable && module load xdsgui/<version>
+which xdsgui generate_XDS.INP   # both under .../xdsgui/<version>/bin
+module list                     # H5ToXds, xds, autoPROC pulled in
+xdsgui                          # on a node with X forwarding; GUI opens
+```
+
+## Adding a new version
+
+Add the new download date under `versions:` in `files/config.yaml`,
+then on a Ra login node: `modbuild build <version>` (modbuild/2.1.2).
diff --git a/xdsgui/build b/xdsgui/build
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+++ b/xdsgui/build
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+#!/usr/bin/env modbuild
+
+pbuild::prep() {
+    :
+}
+
+pbuild::configure() {
+    :
+}
+
+pbuild::compile() {
+    :
+}
+
+pbuild::install() {
+    # upstream ships unversioned binaries at fixed URLs; module version = download date
+    mkdir -p "${PREFIX}/bin"
+    cd "${PREFIX}/bin"
+    wget https://wiki.uni-konstanz.de/pub/linux_bin/xdsgui
+    wget https://wiki.uni-konstanz.de/pub/linux_bin/generate_XDS.INP
+    chmod a+x xdsgui generate_XDS.INP
+}
diff --git a/xdsgui/files/config.yaml b/xdsgui/files/config.yaml
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+++ b/xdsgui/files/config.yaml
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+---
+format: 1
+xdsgui:
+  defaults:
+    group: MX
+    overlay: base
+    relstage: unstable
+  versions:
+    20260818:
+      config:
+        relstage: unstable
+        runtime_deps:
+          - H5ToXds/1.1.0
+          - xds/20260616
+          - autoPROC/20240710
diff --git a/xdsgui/modulefile b/xdsgui/modulefile
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+++ b/xdsgui/modulefile
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+#%Module1.0
+
+module-whatis       "XDSGUI - graphical user interface for XDS data processing"
+module-url          "https://wiki.uni-konstanz.de/xds/index.php/XDSGUI"
+module-license      "free of charge (see module-url)"
+module-maintainer   "MX Data <jiaxin.duan@psi.ch>"
+
+module-help     "
+XDSGUI: a GUI for XDS that visualizes control images and statistics,
+and helps beginners and experts with data processing. Also installs
+the generate_XDS.INP helper script. Loading this module pulls in
+H5ToXds, xds and autoPROC as runtime dependencies.
+"
+
+prepend-path    PATH    $PREFIX/bin