/usr/share/doc/r-cran-tibble/tests/testthat/output/trunc_mat/all--300.txt is in r-cran-tibble 1.4.1-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | # A tibble: 3 x 9
<body created by pillar>
|