Hello pavroo, way12go
First, because mousepad is better than leafpad in every aspect.
Prior to certain version mousepad had outdated xfprint support, so leafpad was basically a mousepad fork with printing improved - and that is, but now mousepad improved by a lot and has tab support - overall much better than leafpad.
So, its certain some people just dont want leafpad in system, in associations and menu.
There is also GTK3 version of leafpad, called l3afpad. People can not want 2-5 editors and terminals for no reason.This is second case.
As for terminal, Xterm is UGLY. It is low on dependency, but has no tab, font, transparency, profiles support.
In XFCE there is Xfce-terminal(with minimal dependencies), in KDE - Konsole, in Gnome - gnome-terminal and so on.
So, why would you want to depend on specific version of terminal? Perhaps you confuse it with depending on specific script interpretor?..
I can imagine, you need some text editor to open some file with, using your program, but it does not need to be leafpad!
Third case, why use leafpad at all, if the correct way to call an editor via alternatives system that launches default graphical editor.https://wiki.debian.org/DebianAlternatives
To set terminal, x-terminal-emulator is used.
For default GUI text editor, gnome-text-editor is used.
Or you can set your own global environiment variable in /etc/environiment or locally ~.bashrc.
I did not expect to meet such misunderstanding
This is a hard dependency to very irrelevant/replacable tools.
No, I am not asking you to change or want to steal them
I just ask to remove dependency on them and call alternative system (above) to call the default system tool for the job. Debian does not allow to go without default terminal or default text editor.
Well, if this is known AND still to much to ask for, please see this as a suggestion. Its certainly a tree in the eye for the fluxbox system I will be building in January on my notebook, but - i can live with it, somehow.