although you have said that this mod is in The Unlicense (Public Domain),
it mean I can do it at will,but I still want to get a comfirmation.

and you mod inspire me doing a big mod,that flatten the whole tech tree,

1.Tier system
that is,all science pack have different levels,included utility,
the all major system in factorio will be shown in earily game,that is, in first hour,you can access belts,logistic network,train,circuit,heatpipes etc..
but it all in very limited way.
for example,utility pack lv1 can unlock logic unit(circuit,but can be mechnical,which can be use in burner phase),
utility lv2 can unlock recycle techs and material unifacation
(
which means something is not really neccary to be steel,
you can even use woods but at higher cost,
it simplify some recipe,pervent unintuitive recipes
)
the next tier require you unlock all thing before their tier.

2.Discovery aand keystone tech
some material can be invest in large amount to early access some tech like "electricity"(overpowered so I put it in late game.)
and discovery tech give key item to unlock keystone tech,and you can early access them,
so if you install some mod with Exporation element,it might be work with it!

3.Iteration Tech
inspire by bob`s module,some tech need certain "prototype" be invest to unlock their upgrade,and it all unlock them.

4.Upgrade tech
like normal infinite tech,now you have different combination to choose from,so if it might be like:

Worker robot speed A-100:
red science10000
Worker robot speed B-10:
red science100
yellow science100
green science100

in terms of raw material,ration is like 10000:300,
it make earily game lab has some meaning to be existed.

and if you can share some thought with me,
plz tell me,I am really really want this done right.

If you really want you can use anything what you find, but I do not really know if you want :D my code is a pretty big mess, hard to understand, so good luck :)
I do not really understand what you wanna make, but looks like it is close to the Industrial Revolution mod tech tree, but doing something like this makes it hard to keep compatible with all others

well, in terms of items,I will have series of recipe call lagacy transformation,it convert my item into vanilla items,

in tech tree,all depandcy is hand make,and not all depancy is not shown in tech tree,they only sort the techs,

so it will be like:
assembler 1-> assembler 2-> assembler 3
but assmbler will require steel,but not shown directly.

and because I flatten the tech tree,so that it should almost not exist any depandcy issue and loops.