[R] question about system.file()

[Ana Marija]

Hello,

I would like to try this example in this link:
https://www.rdocumentation.org/packages/SNPRelate/versions/1.6.4/topics/snpgdsBED2GDS

for example this line:

bed.fn <- system.file("extdata", "plinkhapmap.bed.gz", package="SNPRelate")

I have in current directory from where I would run this function a
file named output4.bed

in order to run the above, can I just run this:
bed.fn <- system.file("output4.bed", package="SNPRelate")

what is "extdata" ? Do I need it if my output4.bed is in the directory
from where I am running this?

Also do I need to have .gz format of output4.bed?

Thanks
Ana