https://github.com/brltty/brltty/pull/419

commit 898350dcbe11bd46d2e3babffe0764169d0a0457
Author: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date:   Sat Jun 17 22:52:42 2023 +0200

    xbrlapi: Do not try to start brltty with ba+a2 when unavailable
    
    When a distribution ships them separately they may not be available, and
    brltty would then flood logs with driver load failure warning every 5
    seconds.

diff --git a/Autostart/X11/90xbrlapi.in b/Autostart/X11/90xbrlapi.in
index ecb2f5e57..cb3e3e5b3 100644
--- a/Autostart/X11/90xbrlapi.in
+++ b/Autostart/X11/90xbrlapi.in
@@ -2,6 +2,7 @@
 
 prefix="@prefix@"
 exec_prefix="@exec_prefix@"
+drivers_directory="@drivers_directory@"
 program_directory="@program_directory@"
 xbrlapi="$program_directory/xbrlapi"
 brltty="$program_directory/brltty"
@@ -9,7 +10,9 @@ brltty="$program_directory/brltty"
 if [ -x "${xbrlapi}" ]; then
   if "${xbrlapi}" 2>/dev/null ; then
     # xbrlapi could connect to BrlAPI, try to start brltty with AtSpi2 driver.
-    if [ -x "${brltty}" ]; then
+    if [ -x "${brltty}" -a \
+         -e "$drivers_directory/libbrlttybba.so" -a \
+         -e "$drivers_directory/libbrlttyxa2.so" ]; then
       "${brltty}" -b ba -s no -x a2 -N 2>/dev/null
     fi
   fi
