[gimp] devel-docs: edit and rename debugging-tips file.

[Jehan <jehanp src gnome org>]

commit f36100978388458787b840d8d6745da59fb5b627
Author: Jehan <jehan girinstud io>
Date:   Sun Feb 13 21:06:43 2022 +0100

    devel-docs: edit and rename debugging-tips file.
    
    Also list it from the devel-docs README.

 devel-docs/README.md                                 |  3 +++
 devel-docs/{debugging-tips.txt => debugging-tips.md} | 11 ++++++++---
 2 files changed, 11 insertions(+), 3 deletions(-)
---
diff --git a/devel-docs/README.md b/devel-docs/README.md
index f310614fe2..0788277163 100644
--- a/devel-docs/README.md
+++ b/devel-docs/README.md
@@ -337,6 +337,9 @@ When writing code, any core developer is expected to follow:
 [GIMP's developer wiki](https://wiki.gimp.org/index.php/Main_Page) can
 also contain various valuable resources.
 
+Finally the [debugging-tips](debugging-tips.md) file contain many very
+useful tricks to help you debugging in various common cases.
+
 ### Newcomers
 
 If this is your first time contributing to GIMP, you might be interested
diff --git a/devel-docs/debugging-tips.txt b/devel-docs/debugging-tips.md
similarity index 93%
rename from devel-docs/debugging-tips.txt
rename to devel-docs/debugging-tips.md
index a6a86d2f18..3d254e36a4 100644
--- a/devel-docs/debugging-tips.txt
+++ b/devel-docs/debugging-tips.md
@@ -7,9 +7,10 @@ newcomers.
 The basic thing is to build babl, GEGL and GIMP with `--enable-debug`.
 
 Note that if you also built glib from source with `--enable-debug`,
-every GObject destroyed are apparently overwritten with values invalid
-as pointers, so dereferencing one after destruction usually leads to a
-crash, which is a good way to find some more vicious bugs.
+every pointers of destroyed GObject are overwritten with `0xaa` bytes,
+so dereferencing one after destruction usually leads to a crash, which
+is a good way to find some more vicious bugs. Also it makes pointers of
+destroyed data easy to spot.
 
 ## Debug logs ##
 
@@ -61,6 +62,10 @@ shortcut, if you first enable with:
 
 See also: https://wiki.gnome.org/Projects/GTK%2B/Inspector
 
+Note also that running GIMP with `GDK_SCALE=2` (or other values) allow
+to test the interface in another scaling than your native one. This
+settings is also available in the GtkInspector.
+
 ## Debugging GEGL code ##
 
 You may encounter this kind of warning upon exiting GIMP: