diff --git a/docs/formatcaps.html.in b/docs/formatcaps.html.in
index 137af258ff..4245d8a850 100644
--- a/docs/formatcaps.html.in
+++ b/docs/formatcaps.html.in
@@ -95,7 +95,47 @@
features
This optional element encases possible features that can be used
- with a guest of described type.
+ with a guest of described type. Possible subelements are:
+
+ - pae
- If present, 32-bit guests can use PAE
+ address space extensions, since
+ 0.4.1
+ - nonpae
- If present, 32-bit guests can be run
+ without requiring PAE, since
+ 0.4.1
+ - ia64_be
- If present, IA64 guests can be run in
+ big-endian mode, since 0.4.1
+ - acpi
- If this element is present,
+ the
default attribute describes whether the
+ hypervisor exposes ACPI to the guest by default, and
+ the toggle attribute describes whether the
+ user can override this
+ default. Since 0.4.1
+ - apic
- If this element is present,
+ the
default attribute describes whether the
+ hypervisor exposes APIC to the guest by default, and
+ the toggle attribute describes whether the
+ user can override this
+ default. Since 0.4.1
+ - cpuselection
- If this element is present, the
+ hypervisor supports the
<cpu> element
+ within a domain definition for fine-grained control over
+ the CPU presented to the
+ guest. Since 0.7.5
+ - deviceboot
- If this element is present,
+ the
<boot order='...'/> element can
+ be used inside devices, rather than the older boot
+ specification by category. Since
+ 0.8.8
+ - disksnapshot
- If this element is present,
+ the
default attribute describes whether
+ external disk snapshots are supported. If absent,
+ external snapshots may still be supported, but it
+ requires attempting the API and checking for an error to
+ find out for sure. Since
+ 1.2.3
+
+