In the table of example values I mixed up the title for the second and third
column: correctly the middle column is the new value and the right column is the
old value.

@salimiles:
Sure, it is src/character.c, l. 274 (
update_secondary_stats_from_primary_stats() ), but I have Version 0.14.1. I am
not sure about whether the line has changed since then.

@ahuillet:
I looked into the source code for it and the only place to_hit was really used
is in src/bullet.c in the function DoMeleeDamage(). Every value over 100 has
exactly the same effect as the value 100. In other words: every dexterity point
over 40 is absolutely useless for the hit chance.

An adequate formula with exp(x) is
hit chance = 100% - 40% * exp(-0.03 * dexterity)

for source code (src/character.c):
l.274: Me.to_hit = 100 - 40 * exp(- (TOHIT_PERCENT_PER_DEX_POINT / 100) *
Me.Dexterity);
l.43: #define TOHIT_PERCENT_PER_DEX_POINT (3.0)

Maybe this is a silly question, but since I am new here, it is maybe ok to ask
silly questions: What is RB and how do I get the actually newest version to
implement it without version conflict? :)

And again some example values:
old:     the old formula
prop I:  the formula from my first post (with 0,97)
prop II: the formula from this post (with exp)
dex	prop I	prop II	old
0	60%	60%	60%
5	66%	66%	65%
10	71%	70%	70%
15	75%	74%	75%
20	78%	78%	80%
25	81%	81%	85%
30	84%	84%	90%
35	86%	86%	95%
40	88%	88%	100%
45	90%	90%	105%
50	91%	91%	110%
55	93%	92%	115%
60	94%	93%	120%
65	94%	94%	125%
70	95%	95%	130%
75	96%	96%	135%
80	97%	96%	140%
85	97%	97%	145%
90	97%	97%	150%
95	98%	98%	155%
100	98%	98%	160%