diff --git a/docs/libcurl/curl_easy_escape.md b/docs/libcurl/curl_easy_escape.md
index b10500ac26..1480a75c59 100644
--- a/docs/libcurl/curl_easy_escape.md
+++ b/docs/libcurl/curl_easy_escape.md
@@ -30,7 +30,8 @@ char *curl_easy_escape(CURL *curl, const char *string, int length);
 This function converts the given input *string* to a URL encoded string and
 returns that as a new allocated string. All input characters that are not a-z,
 A-Z, 0-9, '-', '.', '_' or '~' are converted to their "URL escaped" version
-(**%NN** where **NN** is a two-digit hexadecimal number).
+(**%NN** where **NN** is a two-digit hexadecimal number). Although not
+constrained by its type, the returned string may not be altered.
 
 If *length* is set to 0 (zero), curl_easy_escape(3) uses strlen() on the input
 *string* to find out the size. This function does not accept input strings
diff --git a/docs/libcurl/curl_easy_unescape.md b/docs/libcurl/curl_easy_unescape.md
index 2e78ad5d9f..49e4c6bf26 100644
--- a/docs/libcurl/curl_easy_unescape.md
+++ b/docs/libcurl/curl_easy_unescape.md
@@ -30,7 +30,8 @@ char *curl_easy_unescape(CURL *curl, const char *input,
 This function converts the URL encoded string **input** to a "plain string"
 and returns that in an allocated memory area. All input characters that are URL
 encoded (%XX where XX is a two-digit hexadecimal number) are converted to their
-binary versions.
+binary versions. Although not constrained by its type, the returned data may
+not be altered.
 
 If the **length** argument is set to 0 (zero), curl_easy_unescape(3)
 uses strlen() on **input** to find out the size.
diff --git a/docs/libcurl/curl_escape.md b/docs/libcurl/curl_escape.md
index c24d1890d4..967d375a97 100644
--- a/docs/libcurl/curl_escape.md
+++ b/docs/libcurl/curl_escape.md
@@ -31,7 +31,8 @@ Obsolete function. Use curl_easy_escape(3) instead.
 This function converts the given input **string** to a URL encoded string
 and return that as a new allocated string. All input characters that are not
 a-z, A-Z or 0-9 are converted to their "URL escaped" version (**%NN** where
-**NN** is a two-digit hexadecimal number).
+**NN** is a two-digit hexadecimal number). Although not constrained by its
+type, the returned string may not be altered.
 
 If the **length** argument is set to 0, curl_escape(3) uses strlen()
 on **string** to find out the size.
diff --git a/docs/libcurl/curl_getenv.md b/docs/libcurl/curl_getenv.md
index 2cfb58148c..047c913f25 100644
--- a/docs/libcurl/curl_getenv.md
+++ b/docs/libcurl/curl_getenv.md
@@ -29,7 +29,8 @@ curl_getenv() is a portable wrapper for the getenv() function, meant to
 emulate its behavior and provide an identical interface for all operating
 systems libcurl builds on (including Windows).
 
-You must curl_free(3) the returned string when you are done with it.
+You must curl_free(3) the returned string when you are done with it and,
+although not constrained by its type, it may not be altered.
 
 # %PROTOCOLS%
 
diff --git a/docs/libcurl/curl_mprintf.md b/docs/libcurl/curl_mprintf.md
index 4f5c090579..a592cfb3e6 100644
--- a/docs/libcurl/curl_mprintf.md
+++ b/docs/libcurl/curl_mprintf.md
@@ -67,7 +67,7 @@ the value of *ap* is undefined after the call.
 
 The functions **curl_maprintf()** and **curl_mvaprintf()** return the
 output string as pointer to a newly allocated memory area. The returned string
-must be curl_free(3)ed by the receiver.
+may not be overwritten and must be curl_free(3)ed by the receiver.
 
 All of these functions write the output under the control of a format string
 that specifies how subsequent arguments are converted for output.
diff --git a/docs/libcurl/curl_multi_get_handles.md b/docs/libcurl/curl_multi_get_handles.md
index f94436a889..56da272b8a 100644
--- a/docs/libcurl/curl_multi_get_handles.md
+++ b/docs/libcurl/curl_multi_get_handles.md
@@ -41,7 +41,8 @@ are out of sync.
 
 The order of the easy handles within the array is not guaranteed.
 
-The returned array must be freed with a call to curl_free(3) after use.
+The returned array may not be overwritten and must be freed with a call to
+curl_free(3) after use.
 
 # %PROTOCOLS%
 
diff --git a/docs/libcurl/curl_pushheader_byname.md b/docs/libcurl/curl_pushheader_byname.md
index d066ea7b85..e2968fcd46 100644
--- a/docs/libcurl/curl_pushheader_byname.md
+++ b/docs/libcurl/curl_pushheader_byname.md
@@ -33,7 +33,8 @@ elsewhere and it has no function then.
 It returns the value for the given header field name (or NULL) for the
 incoming server push request. This is a shortcut so that the application does
 not have to loop through all headers to find the one it is interested in. The
-data this function points to is freed when this callback returns. If more than
+data this function points to is freed when this callback returns and,
+although not constrained by its type, may not be altered. If more than
 one header field use the same name, this returns only the first one.
 
 # %PROTOCOLS%
diff --git a/docs/libcurl/curl_pushheader_bynum.md b/docs/libcurl/curl_pushheader_bynum.md
index 12555c57f0..2431ff446b 100644
--- a/docs/libcurl/curl_pushheader_bynum.md
+++ b/docs/libcurl/curl_pushheader_bynum.md
@@ -33,7 +33,8 @@ elsewhere and it has no function then.
 It returns the value for the header field at the given index **num**, for
 the incoming server push request or NULL. The data pointed to is freed by
 libcurl when this callback returns. The returned pointer points to a
-"name:value" string that gets freed when this callback returns.
+"name:value" string that gets freed when this callback returns; although
+not constrained by its type, this string may not be altered.
 
 # %PROTOCOLS%
 
diff --git a/docs/libcurl/curl_slist_append.md b/docs/libcurl/curl_slist_append.md
index b2766f728d..3ebc19e354 100644
--- a/docs/libcurl/curl_slist_append.md
+++ b/docs/libcurl/curl_slist_append.md
@@ -33,8 +33,8 @@ new list. The specified **string** has been appended when this function
 returns. curl_slist_append(3) copies the string. The **string** argument must
 be a valid string pointer and cannot be NULL.
 
-The list should be freed again (after usage) with
-curl_slist_free_all(3).
+The list should be freed (after usage) with curl_slist_free_all(3).
+Its nodes and pointed content may not be altered outside this function.
 
 # %PROTOCOLS%
 
diff --git a/docs/libcurl/curl_unescape.md b/docs/libcurl/curl_unescape.md
index 2600f14361..453fd53145 100644
--- a/docs/libcurl/curl_unescape.md
+++ b/docs/libcurl/curl_unescape.md
@@ -33,7 +33,8 @@ Deprecated. Use curl_easy_unescape(3) instead.
 This function converts the URL encoded string **input** to a "plain string"
 and return that as a new allocated string. All input characters that are URL
 encoded (%XX where XX is a two-digit hexadecimal number) are converted to
-their plain text versions.
+their plain text versions. Although not constrained by its type, the returned
+data may not be altered.
 
 If the **length** argument is set to 0, curl_unescape(3) calls
 strlen() on **input** to find out the size.
diff --git a/docs/libcurl/curl_url.md b/docs/libcurl/curl_url.md
index 5872134e13..8053e630b8 100644
--- a/docs/libcurl/curl_url.md
+++ b/docs/libcurl/curl_url.md
@@ -38,6 +38,9 @@ single URL. When the object is first created, there is of course no components
 stored. They are then set in the object with the curl_url_set(3)
 function.
 
+The object must be destroyed with a call to curl_url_cleanup(3) when no
+longer needed.
+
 # %PROTOCOLS%
 
 # EXAMPLE
diff --git a/docs/libcurl/curl_url_get.md b/docs/libcurl/curl_url_get.md
index a9bb0bdc23..bed1c02f17 100644
--- a/docs/libcurl/curl_url_get.md
+++ b/docs/libcurl/curl_url_get.md
@@ -43,6 +43,7 @@ allocated string with the contents.
 The *flags* argument is a bitmask with individual features.
 
 The returned content pointer must be freed with curl_free(3) after use.
+Although not constrained by its type, the pointed string may not be altered.
 
 # FLAGS