/usr/share/doc/r-cran-pillar/tests/testthat/out-native/letters-long.txt is in r-cran-pillar 1.0.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | <chr>
abcdefghijklmnopqrstuvwxyz
<NA>
|