WSLg flatpaks: modern Nautilus.Devel + Epiphany 50.3, GTK scale 0.75, btop -p 3 default

Multiple operator-flagged fixes 2026-05-10:

1. Nautilus old-looking ("you hard coded an old version of gnome
   files flatpak"). Root cause: Flathub's org.gnome.Nautilus is
   END-OF-LIFE (pinned to GNOME 3.28 runtime, years out of date).
   Fedora flatpak registry doesn't carry Nautilus at all. The
   ONLY modern flatpak Nautilus is org.gnome.Nautilus.Devel on
   the gnome-nightly remote -- ships current 50.x+ libadwaita
   with the modern rounded-corner decorations. Added override
   file at /var/lib/flatpak/overrides/org.gnome.Nautilus.Devel
   with the same cairo+software+dark-scheme env as the rest.

2. Epiphany same story: switched install source from flathub
   (potentially also EOL) to fedora flatpak remote (50.3, current).

3. GTK apps too large: operator-flagged "gnome scaling of apps is
   probably 25% too big relative to windows application windows".
   Added GDK_DPI_SCALE=0.75 + QT_FONT_DPI=72 to
   /etc/profile.d/mios-wslg-gpu.sh AND every flatpak override.
   25% smaller GTK rendering matches Windows-native UI size on
   high-DPI Windows hosts (RTX 4090 / 4K-class displays).

4. btop preset: operator-flagged "btop -p 3 is the correct
   profile -- make it default launch to preset 3 and have the
   background be uncolored so we can utilize the Windows acrylic
   rendering -- make btops colorpalette match and preset 4 to
   be only showing processes section". /etc/profile.d/mios-btop.sh
   (NEW) wraps btop to default `-p 3` (cpu+mem full) when no
   explicit -p/--preset arg is passed. Operator overrides win
   (btop -p 4, btop --preset 1, etc. pass through).

Companion mios-bootstrap commit:
  - mios.toml [desktop].flatpaks: gnome-nightly:org.gnome.Nautilus.Devel
    + fedora:org.gnome.Epiphany (replacing old ids)
  - build-mios.ps1 overlay: adds gnome-nightly remote + appstream
    refresh; FLATPAK_SHORT map updated with the new ids
  - src/btop/btop.conf: presets reordered (slot 3 = cpu mem:0,
    slot 4 = proc:0), shown_boxes = "cpu mem" so even unwrapped
    btop loads with the canonical view

Author: Kabuki94

etc/profile.d/mios-btop.sh

@@ -0,0 +1,33 @@
+# /etc/profile.d/mios-btop.sh
+#
+# Wrap `btop` so plain invocations land on the canonical MiOS preset
+# (preset 3 = cpu+mem full, transparent-bg, mios palette). Operator
+# 2026-05-10: "btop -p 3 is the correct profile -- make it default
+# launch to preset 3 and have the background be uncolored so we can
+# utilize the Windows acrylic rendering".
+#
+# `btop -p 4` (also reachable via `mios proc`-style) shows only the
+# processes section per operator's preset-4 request.
+#
+# Operator can bypass by passing any explicit -p / --preset arg:
+#   btop          -> btop -p 3
+#   btop -p 4     -> btop -p 4         (operator override wins)
+#   btop --preset 1 -> btop --preset 1 (operator override wins)
+#
+# Interactive-shell only; cron/scripted btop sees the real binary.
+
+[ -n "${PS1:-}" ] || return 0
+
+btop() {
+    local has_preset=0
+    for arg in "$@"; do
+        case "$arg" in
+            -p|--preset|-p[0-9]*|--preset=*) has_preset=1; break ;;
+        esac
+    done
+    if [ $has_preset -eq 0 ]; then
+        command btop -p 3 "$@"
+    else
+        command btop "$@"
+    fi
+}

etc/profile.d/mios-wslg-gpu.sh

@@ -74,6 +74,24 @@ export WAYLAND_DISPLAY="${WAYLAND_DISPLAY:-wayland-0}"
 # XWayland at /tmp/.X11-unix/X0 -- ensure DISPLAY points there.
 export DISPLAY="${DISPLAY:-:0}"
 
+# ── GTK / Qt scaling on 4K Windows hosts ──────────────────────────
+# Operator-flagged 2026-05-10: "gnome scaling of apps is probably
+# 25% too big relative to windows application windows". WSLg
+# inherits the Windows host's effective DPI scale (typically
+# 1.25 / 1.5 on high-DPI laptops). Linux GTK apps then render at
+# that scale on top of WSLg's own scale -> apps end up ~25% larger
+# than the Windows-native UI they sit next to.
+#
+# Fix: GDK_DPI_SCALE=0.75 (fractional, scales DOWN by 25%). GDK
+# applies this AFTER GDK_SCALE (which is integer-only), so the
+# net effect at GDK_SCALE=1 + GDK_DPI_SCALE=0.75 is rendering at
+# 75% of native. Operators on standard-DPI hosts can override
+# to 1.0 via shell export or ~/.config/environment.d/.
+export GDK_DPI_SCALE="${GDK_DPI_SCALE:-0.75}"
+# Qt apps (eventual Plasma/KDE GUI) honor the same intent via
+# the QT_FONT_DPI knob -- 72 = 75% of the default 96.
+export QT_FONT_DPI="${QT_FONT_DPI:-72}"
+
 # ── Vulkan ICD ──────────────────────────────────────────────────
 # WSLg ships dzn at /usr/share/vulkan/icd.d/dzn_icd.x86_64.json.
 # We don't unset it -- apps that explicitly request Vulkan can

var/lib/flatpak/overrides/app.devsuite.Ptyxis

@@ -8,3 +8,5 @@ GALLIUM_DRIVER=llvmpipe
 LIBGL_KOPPER_DISABLE=1
 WEBKIT_DISABLE_COMPOSITING_MODE=1
 ADW_DEBUG_COLOR_SCHEME=force-dark
+GDK_DPI_SCALE=0.75
+QT_FONT_DPI=72

var/lib/flatpak/overrides/com.github.tchx84.Flatseal

@@ -5,3 +5,5 @@ GALLIUM_DRIVER=llvmpipe
 LIBGL_KOPPER_DISABLE=1
 WEBKIT_DISABLE_COMPOSITING_MODE=1
 GTK_THEME=adw-gtk3-dark
+GDK_DPI_SCALE=0.75
+QT_FONT_DPI=72

var/lib/flatpak/overrides/com.mattjakeman.ExtensionManager

@@ -8,3 +8,5 @@ GALLIUM_DRIVER=llvmpipe
 LIBGL_KOPPER_DISABLE=1
 WEBKIT_DISABLE_COMPOSITING_MODE=1
 ADW_DEBUG_COLOR_SCHEME=force-dark
+GDK_DPI_SCALE=0.75
+QT_FONT_DPI=72

var/lib/flatpak/overrides/com.vscodium.codium

@@ -5,3 +5,5 @@ GALLIUM_DRIVER=llvmpipe
 LIBGL_KOPPER_DISABLE=1
 WEBKIT_DISABLE_COMPOSITING_MODE=1
 GTK_THEME=adw-gtk3-dark
+GDK_DPI_SCALE=0.75
+QT_FONT_DPI=72

var/lib/flatpak/overrides/org.gnome.Epiphany

@@ -8,3 +8,5 @@ GALLIUM_DRIVER=llvmpipe
 LIBGL_KOPPER_DISABLE=1
 WEBKIT_DISABLE_COMPOSITING_MODE=1
 ADW_DEBUG_COLOR_SCHEME=force-dark
+GDK_DPI_SCALE=0.75
+QT_FONT_DPI=72

var/lib/flatpak/overrides/org.gnome.Nautilus

@@ -8,3 +8,5 @@ GALLIUM_DRIVER=llvmpipe
 LIBGL_KOPPER_DISABLE=1
 WEBKIT_DISABLE_COMPOSITING_MODE=1
 ADW_DEBUG_COLOR_SCHEME=force-dark
+GDK_DPI_SCALE=0.75
+QT_FONT_DPI=72

var/lib/flatpak/overrides/org.gnome.Nautilus.Devel

@@ -0,0 +1,12 @@
+[Context]
+filesystems=xdg-config/dconf:ro;xdg-config/gtk-3.0:ro;xdg-config/gtk-4.0:ro;
+
+[Environment]
+GSK_RENDERER=cairo
+LIBGL_ALWAYS_SOFTWARE=1
+GALLIUM_DRIVER=llvmpipe
+LIBGL_KOPPER_DISABLE=1
+WEBKIT_DISABLE_COMPOSITING_MODE=1
+ADW_DEBUG_COLOR_SCHEME=force-dark
+GDK_DPI_SCALE=0.75
+QT_FONT_DPI=72

var/lib/flatpak/overrides/org.gnome.Software

@@ -8,3 +8,5 @@ GALLIUM_DRIVER=llvmpipe
 LIBGL_KOPPER_DISABLE=1
 WEBKIT_DISABLE_COMPOSITING_MODE=1
 ADW_DEBUG_COLOR_SCHEME=force-dark
+GDK_DPI_SCALE=0.75
+QT_FONT_DPI=72