Merge commit '1bc9dfc5bee'

2 files changed, 32 insertions, 3 deletions

diff --git a/etc/NEWS.29 b/etc/NEWS.29
index 0b651f7a519..d7a6cf7986d 100644
--- a/etc/NEWS.29
+++ b/etc/NEWS.29
@@ -3565,11 +3565,13 @@ font spec.  In these cases, replacing ":weight 'normal" with ":weight
 'medium" should fix the issue.
 
 ---
-** Keymap descriptions have changed.
+** Keymap descriptions by Help commands have changed.
 'help--describe-command', 'C-h b' and associated functions that output
 keymap descriptions have changed.  In particular, prefix commands are
-not output at all, and instead of "??" for closures/functions,
-"[closure]"/"[lambda]" is output.
+not output at all, and instead of "??" for closures/functions, these
+functions output "[closure]"/"[lambda]".  You can get back the old
+behavior of including prefix commands by customizing the new option
+'describe-bindings-show-prefix-commands' to a non-nil value.
 
 ---
 ** 'downcase' details have changed slightly.
diff --git a/etc/PROBLEMS b/etc/PROBLEMS
index 9ef231d4b16..928870c42f6 100644
--- a/etc/PROBLEMS
+++ b/etc/PROBLEMS
@@ -2313,6 +2313,33 @@ recommended way of turning on Font-lock is by typing "M-x
 global-font-lock-mode RET" or by customizing the variable
 'global-font-lock-mode'.
 
+** Colors are not available or messed up on TTY frames inside 'screen'.
+
+This can happen if you have COLORTERM=truecolor defined in the
+environment when Emacs starts, but your version of 'screen' doesn't
+actually support 24-bit true colors.
+
+The COLORTERM environment variable is supposed to be set to the value
+"truecolor" only if the terminal used by Emacs actually supports true
+color.  Emacs does not have any means of verifying that this support
+is available, it takes the fact that the variable is defined to this
+value as an indication that true color support is, in fact, available,
+and uses color setting commands that COLORTERM=truecolor presumes,
+bypassing the usual Terminfo capabilities related to colors.
+
+Some text-mode terminals, such as GNOME Terminal, are known to set
+this environment variable, supposedly to announce their own support
+for true color; however the setting is then inherited by any other
+terminal emulators started from such a terminal, even though those
+other terminal emulators might not themselves support true color using
+the same commands as Emacs uses when it sees COLORTERM=truecolor.
+
+The solution is to either upgrade to a newer version of 'screen'
+(version 5.x or later reportedly supports true color), or to unset the
+COLORTERM variable before starting 'screen', and let Emacs use the
+color support provided by the terminal emulator as defined in the
+Terminfo database.
+
 ** Unexpected characters inserted into the buffer when you start Emacs.
 See e.g. <URL:https://debbugs.gnu.org/11129>