DuckDuckGo rolls the dice!

[Triple Zero]

Check it, query DuckDuckGo for roll 3d12+4 (just below the search input box, above the sponsored link)

It rolls dice for you!

It even supports irregular dice such as 3d19+7. It doesn't support multiple dice (yet) like 1d4+3d6+10

Checking the source code (because yes, DDG is open source) I discovered it also supports another strange format for dice rolling:

roll 4d6 - L

Which I first assumed would roll 4d6 and discard the lowest, like you sometimes do to generate stats for D&D characters, but instead it rolls 4d6, adds them except for the lowest, which it subtracts from the total. Try it out. There is also a format for 3d6-H which subtracts the highest value instead of adding it.

Anyone know what game system such dice rules are used for? I'm curious.

This is the distribution for 4d6-L:

0 |  0.0 %
1 |  0.0 %
2 |  0.1 %
3 |  0.3 %
4 |  0.9 % ==
5 |  1.9 % ====
6 |  3.5 % ========
7 |  5.9 % ==============
8 |  8.9 % ======================
9 | 12.1 % ==============================
10 | 14.6 % ====================================
11 | 15.8 % =======================================
12 | 14.7 % ====================================
13 | 10.8 % ==========================
14 |  6.2 % ===============
15 |  3.1 % =======
16 |  1.2 % ===
17 |  0.3 %