diff --git a/devel-docs/README.md b/devel-docs/README.md
index 5c1979130d..abc4014991 100644
--- a/devel-docs/README.md
+++ b/devel-docs/README.md
@@ -21,87 +21,6 @@ section of GIMP Developer website, with exception of the following:
 
 Take a look at our [porting guide](GIMP3-plug-in-porting-guide/README.md).
 
-## Custom data
-
-This section list all types of data usable to enhance GIMP
-functionalities. If you are interested to contribute default data to
-GIMP, be aware that we are looking for a very good base set, not an
-unfinite number of data for all possible usage (even the less common
-ones).
-
-Furthermore we only accept data on Libre licenses:
-
-* [Free Art License](https://artlibre.org/licence/lal/en/)
-* [CC0](https://creativecommons.org/publicdomain/zero/1.0/)
-* [CC BY](https://creativecommons.org/licenses/by/4.0/)
-* [CC BY-SA](https://creativecommons.org/licenses/by-sa/4.0/)
-
-Of course you are free to share data usable by GIMP on any license you
-want on your own. Providing them as third-party GIMP
-[extensions](#gimp-extensions-gex) is probably the best idea.
-
-### Brushes
-
-GIMP currently supports the following brush formats:
-
-* GIMP Brush (GBR): format to store pixmap brushes
-* GIMP Brush Pipe (GIH): format to store a series of pixmap brushes
-* GIMP Generated Brush (VBR): format of "generated" brushes
-* GIMP Brush Pixmap (GPB): *OBSOLETE* format to store pixel brushes
-* MyPaint brushes v1 (MYB)
-* Photoshop ABR Brush
-* Paint Shop Pro JBR Brush
-
-We do fully support the GIMP formats obviously, as well as MyPaint
-brushes, since we use the official `libmypaint` library. We are not sure
-how well we support other third-party formats, especially if they had
-recent versions.
-
-If you are interested in brushes from a developer perspective, you are
-welcome to read specifications of GIMP formats:
-[GBR](https://developer.gimp.org/core/standards/gbr/), [GIH](https://developer.gimp.org/core/standards/gih/),
-[VBR](https://developer.gimp.org/core/standards/vbr/) or the obsolete [GPB](https://developer.gimp.org/core/standards/gpb/).
-
-If you want to contribute brushes to the official GIMP, be aware we
-would only accept brushes in non-obsolete GIMP formats. All these
-formats can be generated by GIMP itself from images.
-
-If you want to contribute MyPaint brushes, we recommend to propose them
-to the [MyPaint-brushes](https://github.com/mypaint/mypaint-brushes/)
-data project, which is also used by GIMP for its default MyPaint brush
-set.
-
-Otherwise, you are welcome to provide brush set in any format as
-third-party [extensions](#gimp-extensions-gex).
-
-### Dynamics
-
-GIMP supports the GIMP Paint Dynamics format which can be generated from
-within GIMP.
-
-### Patterns
-
-GIMP supports the GIMP Pattern format (PAT, whose
-[specification](https://developer.gimp.org/core/standards/pat/) is available for developers).
-
-This format can be exported by GIMP itself.
-
-Alternatively GIMP supports patterns from `GdkPixbuf` (**TODO**: get more
-information?).
-
-### Palettes
-
-GIMP supports the GIMP Palette format which can be generated from within
-GIMP.
-
-### Gradients
-
-GIMP supports the GIMP Gradient format (GGR, whose
-[specification](https://developer.gimp.org/core/standards/ggr/) is available for developers)
-which can be generated from within GIMP.
-
-Alternatively GIMP supports the SVG Gradient format.
-
 ### Themes
 
 GTK3 uses CSS themes. Don't be fooled though. It's not real CSS in that
@@ -149,18 +68,6 @@ Additionally you can quickly switch between the light and dark variant
 of a same theme by going to "Visual" tab and switching the "Dark
 Variant" button ON or OFF.
 
-### Icon themes
-
-Icon sets (a.k.a. "icon themes") have been separated from themes since
-GIMP 2.10 so you can have any icon theme with any theme.
-
-To know about icons, go to [gimp-data/icons](https://gitlab.gnome.org/GNOME/gimp-data/-/blob/main/icons/README.md?ref_type=heads).
-
-### TODO: Tool presets
-
-
-## TODO: GIMP extensions (*.gex*)
-
 
 ## Core development