What leads the first element of a printed list to be enclosed with backticks in R v3.5.1?

Recently I updated R to 3.5.1 on may Windows 10 with RStudio v1.1.453. I am interested why the first element of a printed list is now always enclosed in backticks? Even if it is a standard name without illegal symbols, e.g., `a` as in this example:

# R 3.5.1
list(a = 1, b = 2, g = 9)
#> $`a`
#> [1] 1
#> 
#> $b
#> [1] 2
#> 
#> $g
#> [1] 9

In previous versions of R, the result looked like this:

# R 3.4.4
list(a = 1, b = 2, g = 9)
#> $a
#> [1] 1
#> 
#> $b
#> [1] 2
#> 
#> $g
#> [1] 9

Do these additional backticks have some meaning? Is it some kind of advancement? Or is it a side effect of some other R functionality? A drawback?

Solution 1:

This is a bug in R 3.5.1 only on Windows. It has been fixed in r-devel as of 17 August 2018.