Dr. Manuel Kuehner
 - This is a follow-up to https://tex.stackexchange.com/questions/588018/.
- The main question is, how to rearrange the branch "4.2" to save vertical space. Ideally, the branch "4.2" is flipped vertically (other ideas are welcome). (see **green** annotation)
- Small additional question: Can I locally (for a specific branch) increase the separation to the neighbor branch? (see **red** annotation)

**Disclaimer:** Cross post (https://tex.stackexchange.com/questions/588083)

----------

\documentclass{article}
\usepackage[edges]{forest}

\begin{document}

\begin{forest}
forked edges,
l sep = 0, for children = {l*= 0.6},
for tree = {
align = center, % needed for "\\" in nodes. Irrelevant for thsi MWE as of now.
draw,
font = \tiny,
},
for descendants={
grow' = 0,
folder,
},
[0
[1]
[\ldots]
[2
[2.1]
[2.2]
[\ldots]
]
[3
[3.1]
[3.2]
]
[4
[4.1
[4.1.1]
[4.1.2]
[4.1.3]
[4.1.4]
[4.1.5]
]
[4.2
[4.2.1]
[4.2.2]
[4.2.3]
[4.2.4]
[4.2.5]
]
]
]
\end{forest}

\end{document}

[![enter image description here][1]][1]

[1]: https://i.stack.imgur.com/KN0lR.png
user 3.14159
Just to show how much daylight there is between some random attempt and a real answer by Sašo Živanović that you will hopefully get. The strategy here is to install folder for all but the root and another node. The manual yshift is ugly, of course.

\documentclass{article}
\usepackage[edges]{forest}
\begin{document}
\begin{forest}
forked edges,
l sep = 0, for children = {l*= 0.6},
for tree = {
align = center, % needed for "\\" in nodes. Irrelevant for thsi MWE as of now.
draw,
font = \tiny,
},
for descendants={% switch on "folder" for all but one descendant
if={level==1&&n==5}{yshift=-1.7ex}{grow' = 0,folder},
},
[0
[1]
[\ldots]
[2
[2.1]
[2.2]
[\ldots]
]
[3
[3.1]
[3.2]
]
[4
[4.1
[4.1.1]
[4.1.2]
[4.1.3]
[4.1.4]
[4.1.5]
]
[4.2
[4.2.1]
[4.2.2]
[4.2.3]
[4.2.4]
[4.2.5]
]
]
]
\end{forest}
\end{document}

![Screen Shot 2021-03-20 at 11.24.24 PM.png](/image?hash=7fd03ace91944be94f26d3e0c7c0e1064bf5af6918034e2e9519f55c87d43066)

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