The class who build this is defined here:
Function name is display_filter()
The line to change is the…latest (161).
Now be warned.
This function is not filterable ( but i may be wrong)
Modifying core files is not best practice as you will loose your change at next update.
Target _blank is kind of deprecated since many years now in favor of user decision. This one just in case you absolutely want to use target argument.