This is equivalent to the path of the script:
%~dp0
This uses the batch parameter extension syntax. Parameter 0 is always the script itself.
If your script is stored at C:\example\script.bat, then %~dp0 evaluates to C:\example\.
ss64.com has more information about the parameter extension syntax. Here is the relevant excerpt:
You can get the value of any parameter using a % followed by it's numerical position on the command line.
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When a parameter is used to supply a filename then the following extended syntax can be applied:
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%~d1 Expand %1 to a Drive letter only - C:
[...]
%~p1 Expand %1 to a Path only e.g. \utils\ this includes a trailing \ which may be interpreted as an escape character by some commands.
[...]
The modifiers above can be combined:
%~dp1 Expand %1 to a drive letter and path only
[...]
You can get the pathname of the batch script itself with %0, parameter extensions can be applied to this so %~dp0 will return the Drive and Path to the batch script e.g. W:\scripts\