The name of the task and the hint are obviously pointing at[robots.txt](https://en.wikipedia.org/wiki/Robots_exclusion_standard), so let'ssee what's there :
```User-agent: *Disallow: /c4075.html```
Now we have a path to check : `/c4075.html`. If we open the page, weimmediately get the flag :`picoCTF{th3_w0rld_1s_4_danger0us_pl4c3_3lli0t_c4075}`