[`curl-prgrs`](https://github.com/Whonix/curl-scripts/blob/master/usr/lib/curl-scripts/curl-prgrs) causes high CPU and even may slow down downloads because of this.
Possible approaches to fix this:
* 1) find a replacement for curl-prgrs in bash, or
* 2) re-implement curl-prgrs in python, or
* 3) [make torbrowser-launcher work with (Qubes-)Whonix](https://forums.whonix.org/t/using-torbrowser-launcher-instead-of-tb-updater-in-whonix)
* 4) find a way to deprecate #tb-updater by [using](https://www.whonix.org/wiki/Dev/Default_Application_Policy#guix) guix (T600) or so. Or not. 
* 5) fix curl-prgrs, perhaps port it to pipeviewer `pv` (T649)
a) Emulate curl options in python:
--fail --tlsv1.2 --proto =https --max-time 180
b) Emulate endless data attack protection.
if [ "$bytes" -gt "$CURL_PRGRS_MAX_FILE_SIZE_BYTES" ]; then
c) Emulate environment variable `CURL_PRGRS_EXEC` processing.
(This is required to update the #tb-updater #msgcollector zenity progress bar.)
if [ "$CURL_PRGRS_EXEC" = "" ]; then
if [ "$percent_last" = "$percent" ]; then
eval $CURL_PRGRS_EXEC $percent
 Keeping #tb-updater has the advantage that it could relatively easily(*) transformed into a tpo-downloader, that can also fetch other software from torproject.org such as Tor Messenger.
(*) Time is an issue.