diff --git a/doomsday/libs/core/include/de/data/list.h b/doomsday/libs/core/include/de/data/list.h
index 9ec18bf28a..3438e3dde8 100644
--- a/doomsday/libs/core/include/de/data/list.h
+++ b/doomsday/libs/core/include/de/data/list.h
@@ -63,7 +63,10 @@ class List : public std::vector<T>
 
     using Base::begin;
     using Base::end;
+    using Base::cbegin;
+    using Base::cend;
     using Base::push_back;
+    using Base::emplace_back;
     using Base::size;
     void pop_front() { removeFirst(); } // slow...
     void push_front(const T &v) { prepend(v); } // slow...
@@ -105,6 +108,7 @@ class List : public std::vector<T>
     void     removeLast()  { Base::erase(Base::begin() + size() - 1); }
     void     removeAt(size_t pos) { Base::erase(Base::begin() + pos); }
     void     removeAll(const T &v) { Base::erase(std::remove(begin(), end(), v), end()); }
+    void     remove(size_t pos, size_t count) { Base::erase(cbegin() + pos, cbegin() + pos + count); }
     bool     removeOne(const T &v)
     {
         auto found = std::find(begin(), end(), v);
diff --git a/doomsday/libs/core/include/de/data/time.h b/doomsday/libs/core/include/de/data/time.h
index 3a5f6f5871..8b01f657fc 100644
--- a/doomsday/libs/core/include/de/data/time.h
+++ b/doomsday/libs/core/include/de/data/time.h
@@ -154,7 +154,7 @@ class DE_PUBLIC Time : public ISerializable
         HumanDate,        ///< human-entered date (only with Time::fromText)
         UnixLsStyleDateTime,
     };
-    
+
     using TimePoint = std::chrono::system_clock::time_point;
 
 public:
@@ -303,6 +303,8 @@ class DE_PUBLIC Time : public ISerializable
 
     static void updateCurrentHighPerformanceTime();
 
+    static Span currentHighPerformanceDelta();
+
     /**
      * Parses a text string into a Time.
      *
diff --git a/doomsday/libs/core/src/data/time.cpp b/doomsday/libs/core/src/data/time.cpp
index 85b115201f..e6196e7c2f 100644
--- a/doomsday/libs/core/src/data/time.cpp
+++ b/doomsday/libs/core/src/data/time.cpp
@@ -531,7 +531,7 @@ Time Time::parse(const String &text, const char *format) // static
         }
         if (is.fail()) return Time::invalidTime();
     }
-    
+
     // Assume missing date values.
     if (year == 0)
     {
@@ -746,6 +746,11 @@ void Time::updateCurrentHighPerformanceTime() // static
     currentHighPerfDelta = highPerfTimer().elapsed();
 }
 
+Time::Span Time::currentHighPerformanceDelta()
+{
+    return currentHighPerfDelta;
+}
+
 std::ostream &operator<<(std::ostream &os, Time const &t)
 {
     return os << t.asText();