Garbage in /tmp

[ThiefMaster]

$ docker run -it --rm perl:5 /bin/bash
root@997cd2767d48:~# cat /tmp/L9sh12pSKR
--- 'this is a string'

---
- 1
- 2
- 3
- 4
- 5

---
alpha: beta
gamma: delta
root@997cd2767d48:~# ls -al /tmp
total 16
drwxrwxrwt 1 root root 158 Feb 17 14:57 .
drwxr-xr-x 1 root root 174 Feb 27 15:23 ..
-rw------- 1 root root  76 Feb 17 14:55 L9sh12pSKR
-rw------- 1 root root  26 Feb 17 14:55 YAML-Tiny-test-ZMaopgIF
-rw------- 1 root root  32 Feb 17 14:55 YAML-Tiny-test-mohloFyk
-rw------- 1 root root  30 Feb 17 14:55 YAML-Tiny-test-sqTpSwoa
root@997cd2767d48:~#

I don't think any of this should be in the image... Probably leftovers from running tests?